Deadlock (episode)
While trying to avoid Vidiian territory, Voyager is nearly destroyed by proton bursts coming from an unknown source.

Summary

Teaser 
Neelix asks Ensign Samantha Wildman to help him in the mess hall. A heating element in his kitchen is malfunctioning, and it won't be long before there won't be any way to cook for the  crew. Since Neelix has her there, he also asks her to help fix one of the food replicators. While investigating the problem, Wildman goes into labor. Neelix is excited for her and escorts her to sickbay. Seven hours later, The Doctor announces Wildman will soon deliver her baby. The bridge crew waits in anticipation.  Tom Paris can't believe how long it takes; he figures she would have had the baby by now. Captain Kathryn Janeway reassures the lieutenant that childbirth takes as long as it takes. Lt. Tuvok adds that the birth of his third child took 96 hours. 

The light conversation is interrupted when Tuvok detects Vidiian subspace communications ahead and a G-type star system containing two inhabited planets, all Vidiians. Janeway doesn't want her or her crew to be unwilling organ donors, so she orders Paris to find a way to avoid detection. Paris suggests traveling through a large plasma drift, which spans almost halfway across the sector, and the crew head in knowing the interference caused by the plasma drift is their best chance to escape the Vidiians.

Back in sickbay, Wildman is beginning to push but suddenly screams in pain as the baby turns awkwardly and lodges its exo-cranial ridge into Wildman's uterine wall. The baby can't be moved for risk of causing nerve damage, but if it isn't delivered soon then the ridges could cause internal bleeding. The Doctor decides to perform a fetal transport and beam the baby out.

Voyager successfully leaves the Vidiian system without being detected, and Janeway orders Paris to leave the plasma drift and resume their previous heading.

In sickbay, The Doctor performs the fetal transport and delivers the baby, a girl. The Doctor notes that the transport caused a small complication that can be fixed with osmotic pressure therapy. Otherwise, she's perfectly healthy.

Just then, the ship hits severe subspace turbulence. The warp engines stall and power failures occur all over the ship. Janeway calls for red alert, and asks Lt. Torres what's happening. It turns out the ship's antimatter is being drained, but Torres can't find any reason why it would be as all the containment fields are in place. Janeway orders Torres to start a series of proton bursts that will keep the antimatter reaction going. Torres prepares to start the procedure, but suddenly a proton burst hits the ship without warning seemingly out of nowhere. Voyager is heavily damaged and people are hurt all over the ship. What's worse, the incubator for Wildman's baby is losing power due to the energy drain. The Doctor asks Kes to switch to an emergency incubator while several injured crew members pile into sickbay.

Act One 
In sickbay, The Doctor attempts to deal with the wounded crewmembers while Kes tries to use osmotic pressure to stabilize the baby's cells, but it is having no effect. Suddenly, another proton burst damages sickbay, and The Doctor tells Kes to increase the pressure. The Doctor is informed that there are more injured crewmembers on the way.

From the massively-damaged main engineering, Torres tells Janeway that the ship is being hit by proton bursts, but she didn't start the proton burst procedure. Ensign Kim confirms that no bursts were fired, and the sensor array which would have emitted them is off-line. Another burst hits, causing a hull breach on deck 15, section 29 alpha and the emergency force fields are off-line. Ensign Kim tells Captain Janeway that he has been working on a portable force field generator which could seal the breach, and Janeway sends him to try it.

Back in sickbay, The Doctor treats an injured Neelix while Kes is struggling with the baby, whose condition starts to deteriorate due to the cell imbalance. The Doctor prepares to help, but suddenly another burst hits, causing damage to The Doctor's program, almost knocking him off-line.

Torres and Kim reach the breach on Deck 15 Section 29. Assisting them is Lt. Hogan, and Torres and Kim go off to the breach while Hogan tries to re-route the power to them.

Tuvok has fully analyzed the proton bursts and still has no idea where they're coming from, but by now Janeway is more concerned with stopping them. She tells Commander Chakotay to magnetize the hull to minimize the effects of the bursts. She works with him to transfer enough power to protect the ship.

The Doctor stabilizes his program, but by now the baby is unconscious. The Doctor prepares to try and resuscitate her and promises Wildman he'll do everything he can to save the baby, but by now things are looking very bleak.

Hogan is about to re-route the power, when suddenly another proton burst hits and blows out the panel he's working at injuring him. Torres and Kim don't have time to go back, and continue on to the breach.

In sickbay, all attempts to resuscitate the baby have failed and The Doctor is forced to declare her dead. Wildman is devastated and begins to sob while Neelix comforts her. Hogan calls sickbay for help, and Kes grabs a medkit and heads to his position. 

Meanwhile, the breach is widening and Torres decides they need to leave. However, Kim hesitates and suddenly the ship is hit with a huge jolt causing Kim to fall. He grabs a railing, but is hanging directly above the breach. Torres tries to grab him, but the force of the vacuum is too strong and he is pushed into space, killing him. Torres comes out of the Jefferies tube into the corridor to help Hogan. Kes runs down the corridor to help, but she vanishes into thin air.

Act Two 
Torres tells Janeway what has happened to Kim and Kes and informs her of the spatial rift that has opened on deck 15. She throws a piece of broken conduit into the rift and scans the fissure. She notes that there is an oxygen-nitrogen atmosphere on the other side; Kes might still be alive. With the hull breach widening, Janeway orders that the entire deck be evacuated. Torres helps Hogan to his feet and the two of them make their way out of the area.

Chakotay is able to draw enough power to magnetize the hull and minimize the effects of several proton bursts. Janeway orders a full damage report from Tuvok. The news isn't good: the deck 15 breach had widened to encompass a part of deck 14, and 632 microfractures are all over the hull. All primary systems are offline, the antimatter levels are at 18 percent and continuing to fall, the warp coils in both nacelles are fused and inoperative, 15 crew members have plasma burns and 27 others are injured. The Doctor has opened triage facilities in both sickbay and holodeck 2. Tuvok also reports that Wildman's baby has died. Janeway first shows a sign of sadness, then anger. She orders the microfractures sealed and tells Paris to go to help the wounded.

Just then, the proton bursts start to cause damage again. The power feeding the magnetized hull shuts down and the hull begins depolarizing. Fires erupt everywhere, but aren't put out because the automatic fire suppression system is also offline. The computer then reports that a hull breach has appeared on the bridge and, with the emergency force fields offline and no way to seal the breach, Chakotay begins an evacuation. Janeway stays at her command chair, trying to re-route emergency power to the field emitters to seal the breach. Chakotay yells at her to leave the bridge before it is too late. As more of the bridge begins to crumble, Janeway finally leaves to join the other evacuees. As she evacuates, she takes one last look at the bridge and freezes in disbelief – she sees a ghost-like image of her bridge crew. In fact, she's staring at herself sitting in her chair. Chakotay yells once more and Janeway leaves the bridge.

On an undamaged bridge, the Janeway in the chair (Janeway #2) sees herself (Janeway #1) cross the bridge and enter a turbolift. Janeway #1 has a tinge of orange from the fires that erupted on the first bridge. This Janeway sits on an unaffected ship; gone are the breaches, injuries, and damage. The proton burst procedure is occurring normally. Janeway #2 in shock tells a very much alive Harry Kim to scan the bridge because she says she saw herself... and she looked like hell. Kim reports that he found a spatial fluctuation, but it was gone in a millisecond. He can't get a more precise reading because the sensors are being used for the proton bursts. Janeway asks Torres to speed up the procedure from its normal three hours so she can use the sensor array to find out what happened.

In sickbay, Wildman holds a healthy baby girl. Janeway goes to congratulate her and asks The Doctor about a mysterious crewmember they found unconscious on deck 15: the Kes from the first Voyager (Kes #1). The Kes from the second Voyager says Kes #1 is nearly identical to her in every way, except for a phase shift in her DNA.

Act Three 
Kes #1 recounts the events of the severe damage on her Voyager. She says she ran through a corridor, then she felt dizzy and she woke up there in Sickbay. Janeway #2 says her crew found a piece of conduit from bulkhead 052 on deck 15, section 29 Alpha, even though there were no signs of damage. Kes #1 disagrees, saying there was massive damage to deck 15. Janeway #2 walks Kes #1 through the events after they left the plasma drift. Since Kes #1's Voyager had not started the proton burst procedure, Janeway #2 realizes that the proton bursts from their Voyager is damaging the other one. Janeway #2 tells her Torres to stop the proton burst procedure. The bursts stop, but the drain on antimatter starts once again. Janeway #2 knows the only way to figure out how to get out of the situation is to find the first Voyager, so she heads to the bridge for more information. Chakotay #2 runs a quantum level analysis on the ship's sensors after they left the plasma drift and hit the spatial turbulence. Torres #2 explains that it was more than just turbulence, it was a subspace divergence field. After the ship left the drift, all sensor readings doubled... every particle of matter was duplicated. The field created another Voyager, occupying the same point in space-time.

Janeway #2 recounts a Kent State University experiment in which quantum theorists duplicated a single particle of matter using divergence of subspace fields called a spatial scission. The theorists failed when they tried to duplicate antimatter. The experiment explains why Voyagers power was draining so fast; both ships are running their engines from the same antimatter source, like Siamese twins linked together at the heart. Janeway #2 asks Torres #2 to figure out a way to communicate with the other ship. She also wants to find a way to get Kes #1 back to her ship without being harmed. Kim works on a phase discriminator to protect Kes #1 from the effects of the spatial rift.

Back in sickbay, Wildman #2 asks The Doctor #2 when she can start breastfeeding her baby. The Doctor says she can start immediately, although they'll have to think of alternatives once her baby's Ktarian incisors form in three to four weeks. The sound of the baby crying brings back Kes #1's memory of the first Wildman's baby dying in her sickbay. The Doctor tries to comfort her and says it's not her fault. Kes #1 wants to go back to her ship to help her crew. The Doctor tells her not to worry; he should have a counterpart that is well-programmed to handle the situation.

Janeway #2 and Torres #2 try to figure out a way to communicate with the first Voyager. Janeway orders Torres to emit a comm signal through all subspace bands to get their attention. The comm signal pronounces itself as a shrill noise that permeates into engineering (which, due to the bridge being uninhabitable, is the crew's temporary command center) of Voyager #1. Voyager #1 locks onto the phase variance of the communique and sends back the signal. Torres #2 sends a message to the first Voyager using the ship's emergency encryption code to begin communicating at a frequency of 12 GHz. The viewscreen behind the engineering console springs to life, and the face of Janeway #2 appears. The two Janeways meet for the first time.

Janeway #1 and her crew discuss whether the second Voyager is a deception but Janeway #1 tends to believe Janeway #2. Janeway #1's counterpart knew intimate information about her and her crew, including when she walked seven kilometers in a severe thunderstorm after she had lost a tennis match. Janeway #1 decides to cooperate with her and coordinate an attempt to try to merge the two ships. Janeway #1 takes command of the effort and orders both Torres' to synchronize a depolarization pulse with the deflector dish. The pulse doesn't work and results in the ships going further out of phase. The phase separation threatens to destroy both ships, so the plan is aborted. The stress of the procedure breaks the comm link and turns the antimatter leak into a hemorrhage, meaning the ship will be out of power in thirty minutes. Running out of time, Janeway #2 asks Kim #2 if he's ready to send Kes #1 back to her ship. He replies that he is ready. Janeway #2 tells him to rig another phase discriminator; she plans to go to the other Voyager and coordinate operations with Janeway #1.

Act Four 
Janeway #1 is attempting to figure out how to stop the leak of antimatter when Janeway #2 shows up in engineering to talk to her. The two Janeways go to the top level of engineering to try to determine how to fix the problem. Janeway #1 thinks of separating the two ships, but Janeway #2 says that's impossible because her Torres says interaction between the two ships' antimatter would cause the ships to destroy themselves. Janeway #2 wonders if Janeway #1 could move her crew to her undamaged ship. Janeway #1 says that is impossible, because her Torres says that moving more than five or ten people at a time would harmfully adjust the atomic balance of the two Voyagers, once again destroying both ships. Janeway #1 tells Janeway #2 to go back to her ship to run a metallurgical analysis on the hull. Janeway #2 already knows what her counterpart is going to do – destroy her ship and allow Janeway #2's intact ship to continue on its journey – and convinces her to wait for fifteen minutes to think of another way.

Back on her own bridge, Janeway #2 hails her counterpart and begins to describe an idea she's had when both Tuvoks detect a Vidiian ship heading toward them. The effects of the power loss and proton bursts have caused the weapons and shields on both ships to go offline. Tuvok #2 calculates it would take three hours to restore the weapons system to the undamaged ship. The Vidiians are aware of this and fire a Hyper-thermic charge. The charge results in a direct hit but only the second ship feels the effect, its weapons array is destroyed. The Vidiians land their ship on the hull of the second Voyager and cut an access port onto deck 5.

Act Five 
Vidiians board the second Voyager and begin killing the crew and harvesting their organs. A Vidiian kills Tuvok and a security guard. In sickbay (on deck 5), The Doctor tells Wildman that he will keep her baby safe, planning to hide her in an access port. The Doctor erects an emergency force field around Sickbay to protect them, but it doesn't hold for long and two Vidiians storm into the room while The Doctor is forced to hide in his office with the baby.

Back on the bridge, Chakotay reports the Vidiians have taken Sickbay and everything below deck 5. There are 347 Vidiians on the ship and more are boarding. Janeway #1 hails the second Voyager and offers to help by sending a security team to fight the Vidiians, but Janeway #2 refuses. She decides to use the auto-destruct sequence to prevent both ships from falling into Vidiian hands. Janeway #2 tells Janeway #1 that it only seems fair for her to send Harry Kim through the spatial rift with Wildman's baby. Kim protests, but Janeway #2 orders him to get the baby and go, saying he's got five minutes to get through the rift. As Kim leaves the bridge, Janeway #2 sets the auto-destruct for five minutes and tells the computer to disable voice warnings. She and Chakotay #2 sit down in their command chairs and grimly look at each other before she enables the countdown.

Kim makes his way to sickbay where the Vidiians, having killed everyone inside apart from the hidden baby, are scanning Kes #2 and Wildman #2 for organs. They notice that Wildman has just given birth. They begin scanning for the baby, who is huddled in The Doctor's arms in his office. Kim bursts in and kills the Vidiians. The Doctor hands over the baby and tells Kim to tell The Doctor on the other ship that he has corrected the baby's hemocythemia.

Back on the bridge, two Vidiians walk off the turbolift. Janeway stands and gives them a calm welcome: "Hello. I'm Captain Kathryn Janeway. Welcome to the bridge." The Vidiians are puzzled at the welcome, when suddenly one of the Vidiians alerts the other to the auto-destruct countdown as it enters the final few seconds, far too late to do anything about it. The countdown reaches zero and the second Voyager explodes, which also destroys the Vidiian ship, while leaving the first Voyager intact.

Ensign Kim makes it safely through the rift with Wildman's baby. Chakotay informs Janeway of the destruction of the other Voyager and the Vidiian ship. Janeway is saddened at the deaths, but knows it was what they had to do.

"Captain's log, stardate 49548.7. There are no signs of any pursuing Vidiian vessels and we have resumed a course toward home."

Voyager continues on its way and the crew starts to makes repairs. There are no signs of the Vidiians, while it will be three days before the crew can return to the bridge. Tuvok and Janeway have a discussion about their experience, and Janeway admits that after going over what happened, if the Vidiians hadn't attacked, she would have destroyed her ship but she could also see the other Janeway's point of view. Tuvok comments that Janeway was "both the doubter and the doubted" and notes the paradoxial logic at work in the situation. Ensign Wildman thanks Kim for reuniting her with her baby, but he tells her it was the other Doctor who saved her from the Vidiians. Kim and Janeway walk out into the corridor where he comments that it's weird that he's on a different ship with a different captain and a different crew, except she is his captain and there is really no difference. Janeway says that being Starfleet officers, weird is part of their job.

Memorable quotes 
"Uhh..."
"What's wrong?"
"I think I'm having a contraction... Oh yeah, it's a contraction alright."
"Oh that's wonderful. Labor can't be far behind. We're having a baby."
 - Wildman and Neelix 

"The Delta Quadrant isn't anybody's idea of a playground."
 - Janeway

"Push, ensign."
"You push! Dammit! I'm sick of pushing!"
 - The Doctor and Wildman, while Wildman was in labor
(Closed Captions throughout this episode refer to The Doctor as “Dr. Zimmerman”)

"I'm just not sure if I should be welcoming it aboard or apologizing."
 - Janeway, feeling guilty about Naomi Wildman being born far from home

"My father had a saying, captain. 'Home is wherever you happen to be'."
 - Chakotay

"This is ridiculous. It's been seven hours. How long does take to deliver a baby?"
"As long as it takes Mr. Paris."
"Indeed. During the birth of our third child my wife was in labor for 96 hours."
"Four days?"
"I have learned that pregnancy and patience go hand-in-hand."
 - Paris, Janeway, Tuvok, and Kim 

"Ensign Kim, scan the Bridge. I just saw myself cross the Bridge and enter that turbolift. It was very faint, almost like a ghost image. And I looked like hell."
 - Janeway, after having just having faintly observed herself on the duplicate Voyager

"This isn't really my ship and you're not really my captain and yet you are and there's no difference. But I know there's a difference. Or is there? It's all a little weird."
"Mr. Kim, we're Starfleet officers. Weird is part of the job."
 - Kim and Janeway

"Please don't make me call security and have you escorted off my ship, because... you know, I'll do it."
 - Janeway #1, to Janeway #2, when the two disagree about how to proceed

"Make me a promise, Kathryn: get your crew home."
"I will. I will."
- Janeway #2, to Janeway #1, as she decides to sacrifice her ship

"Harry, you've got five minutes, get the baby."
"But captain... "
"Move it ensign, that's an order!"
 - Janeway and Kim

"Warning, self-destruct sequence has been initiated. Warp core overload in four minutes, fifty-five seconds. There will be no further audio warnings."
 - Computer

"Hello. I'm Captain Kathryn Janeway. Welcome to the bridge." 
 - Janeway #2, to a group of Vidiians, three seconds before the second Voyager initiates self-destruct

"Mr. Kim, we're Starfleet officers. Weird is part of the job."
 - Janeway, to Kim, when discussing how he is from a parallel reality

Background information

Story and script 
Brannon Braga's initial idea for this episode involved toying with narrative structure. The writer and supervising producer explained, "I just thought it would be really bizarre if you told a story for an act or two and suddenly you found yourself in the middle of a different story on a different Voyager, but they're occupying the same point of time and space." Executive producer Jeri Taylor said of the outing, "It was one of those intricate little puzzles that Brannon loves to do." (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages)
Another motive for writing the story was to bring elements to the series that it was lacking at that point. Brannon Braga noted, "We needed a show that was pure action and pure high-concept sci-fi." (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages)
Previous episodes featuring duplicates – particularly, unsuccessful development of one such story for  – influenced the writing team's approach to this installment. Jeri Taylor clarified that, as a result of the difficulties pertaining to the aforementioned TNG plot, Voyagers writing staff approached the idea for this episode "with some trepidation." (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages)
According to Jeri Taylor, the solution was to focus the story on fewer characters, such as by killing off one of the two Harry Kims and having Kes be unconscious throughout most of the episode. This concentrated the story on the two Janeways and their collaboration. (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages)
The references to Kent State University in this episode constitute an in-joke, as Brannon Braga studied Theater Arts and Filmmaking there.
The episode's final script draft was submitted on .

Cast and characters 
Actress Kate Mulgrew quite enjoyed playing two different versions of her usual character, Captain Janeway. "Janeway against Janeway! Talk about green screen. Split screen. Every conceivable kind of screen," Mulgrew remarked, before indicating a small gap with the thumb and forefinger of her left hand. "I was acting within an eighth of an inch! I loved doing that episode [...] To play... against yourself, creating yourself. It was... the most arduous and possibly the most satisfying work I've ever done, technically." (VOY Season 2 DVD)
Hogan actor Simon Billig liked this episode. "I enjoyed doing 'Deadlock'," he noted, "because it was so action-oriented [...] I got to see a lot of great effects and how they're done and that was great fun." (TV Zone, Issue 93, p. 32)
This episode attained high praise from Paris actor Robert Duncan McNeill, especially its use of the Vidiians. "Deadlock' was good [...] They were great in that one," McNeill opined. (, issue #231, p. 49)
Kim actor Garrett Wang's favorite stunt of the series was for this episode. He explained, "Kim is secretly running through the corridor, and he can detect that there are Vidiians in [sickbay]. He knocks out one or two of the guys when he busts in through the door, but then the third guy shoots at him, and Kim gets to do a little flip, which was my favorite stunt. It was a running forward roll [...] and that was my favorite little Jackie Chan-esque stunt." ()

Production 

 The scene from this installment in which Hogan is blasted backwards by an exploding panel was filmed with a stunt performer. "It was the first time I ever really had a stunt double," Simon Billig noted. (TV Zone, Issue 93, p. 32)
 The running forward roll that Kim does was improvised by Garrett Wang on the set. The actor recalled, "I learned [it] in stage combat class back in college. The director, David Livingston, said, 'Okay, come in, shoot this guy, shoot this guy, duck and then pop back up and shoot the third guy.' I said, 'Why don't I shoot the first guy, shoot the second guy, and then run forward and do a dive to duck below the phaser fire of the third guy, and then as I pop up from the forward roll, shoot the last guy?' So I did the first practice, and all the crew went, 'Oooh!' Then I did it for real." (Star Trek Magazine issue 106, p. 41)
One major concern during production was that the episode would not be long enough. Jeri Taylor recalled, "It was directed with such incredible pace by David that it was one of those shows we had to add scene after scene after scene to because it was short. We ended up shooting something like another day and a half just to bring it to time. So it moves like a house on fire!" () Taylor also said, "The show came out enormously short [...] It was like eight or nine minutes short, and we kept writing scenes, and they just kept getting gobbled up on those stages. It's much better to be long than to be short. There's never any accounting for it. Why is one seventy-page script eight minutes long and with this one, with the same director, we had seventy-five pages and had to shoot two extra days to get enough material to make it long enough? It was not an inexpensive show as a result, but what I was pleased about was I would defy anybody to know what the added material is. It is seamless. Some of the added scenes are some of the better scenes. They do not stand out as fill at all." (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages)
According to Kate Mulgrew, she not only enjoyed working on this episode but also "had the right guy, too." She added, "[David] Livingston was terrific." (VOY Season 2) Jeri Taylor was similarly complimentary about the director's work on this episode, remarking, "David Livingston did an outstanding job with the direction." (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages)
The episode was somewhat difficult to film. Brannon Braga remarked, "It was extremely tough to shoot." (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages)

Effects 
The shot of Harry Kim floating into space, much to Torres' distress, involved several effects methods. "We shot Garrett [Wang] against a blue screen for that," visual effects producer Dan Curry recalled. "The wind was, of course, done by special effects wind generators, and so that was it. And then space outside was something we created in post, and then we had to trace or rotoscope the hole in the ship and then the space that Garrett would fall out in blue screen. And then, of course, because the light would change from one section to another as he was passing into space, we had to make sure that there was something that would change the light as he hit the new environment outside the ship. A simple shot like that, that could take a few seconds of screen time, might represent two hundred man hours." (Red Alert: Visual Effects Season 2, VOY Season 2 DVD special features)

Continuity 
 This episode features the first of fives times that the destruction of Voyager is depicted on the series. On this occasion, a phase-shifted duplicate of the ship is self-destructed.
This episode depicts Voyagers fourth encounter with the Vidiians, after the episodes ,  and .
This is the first of two times, over the course of the series, where Janeway meets herself face-to-face; the second such occasion is in the series finale, . Janeway also watches herself walking down a corridor in the Season 5 episode .
This episode marks the second of three times that Harry Kim "dies" during Voyagers seven-year trip, the other times being in  and .
 This episode features the second of nine times that Kathryn Janeway's death is depicted over the course of the series. The previous episode that depicted this was . On this occasion, the version of Janeway that succumbs to death is a phase-shifted duplicate, and the cause of death is the self-destruction of Voyager.
One of the Vidiian intruders scans Tuvok and identifies him as a Vulcan. It is not explained how the Vidiians would be familiar with Vulcans, as Tuvok had not previously had any encounter with the Vidiians where they would have had an opportunity to learn the name of his species or scan him.
At the end of this episode, the Doctor states that he is programmed to be heroic when he needs to be. This may be a reference to the first-season episode "Heroes and Demons", where he plays the hero in a holodeck version of Beowulf.
The version of Janeway on the ultimately destroyed Voyager asks her counterpart on the surviving Voyager to promise to get her crew home. She agrees to make this promise and ultimately delivers on it, getting Voyager and its crew home in the series finale, .
This episode shares some common themes with the  episode . Both show the destruction of the space station/starship and both Miles O'Brien and Harry Kim die and are replaced by alternate versions of themselves, with the characters then voicing reservations about their place in this timeline.
Reference to 47: At one point in the episode, Torres cycles through 47 different communication frequencies. Later, the Harry Kim of the second Voyager tells that the ship has been boarded by 347 Vidiians and more others are coming. 
This episode has the longest teaser in Voyagers second season.
The Doctor has the sleeves of his uniform rolled up (similar to Miles O'Brien's in the first five seasons of Star Trek: Deep Space Nine) in this episode.

Story arcs 
 The Doctor's quest to find a name, introduced in  and revisited in four further episodes, is briefly revisited in this episode, when the Doctor on the surviving Voyager asks Kim if his counterpart on the destroyed Voyager had given himself a name.
The ongoing story of Samantha Wildman’s pregnancy, introduced in  and revisited in , is concluded in this episode with the birth itself. Conception had happened before Voyagers arrival in the Delta Quadrant, and this extremely long gestation period was later explained in the sixth season episode  as having been a consequence of the baby's half-Ktarian genes.

Self-destruct sequence 
This episode marks the second of three times that Voyagers self-destruct is initiated (after ), and is the only time in a television episode where it is not cancelled.
Unlike in other Star Trek incarnations, in this episode (as with the previous activation in ), when Janeway initiates the self-destruct sequence for Voyager, the computer does not ask for concurrent authorization from any other member of the bridge crew.
This episode reveals that the computer's vocal warnings during a self-destruct sequence can be silenced. This option would be used again in Star Trek: First Contact.
When the Vidiians enter Voyagers bridge, they are greeted by the computer displaying the countdown for the self-destruct sequence as it enters the last few seconds, similar to when a Klingon invasion party boards the  in .

Reception 
Brannon Braga thinks very highly of this episode. He noted, "I thought it turned out well." (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages) In a  interview, he elaborated, "I thought 'Deadlock' was classic Star Trek and whatever crew would have been in that episode, it would have been a good episode of Star Trek."  Ultimately, the moment from this installment that Braga liked the best was the first transition from the perspective of one Voyager, in a situation of disarray, to the other Voyager, depicted as being much calmer. (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages)
Jeri Taylor thought this episode "came out very well," largely due to limiting the number of duplicates in the story. "It gave it a focus and a limitation that I think helped the storytelling," she enthused. (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages) Taylor also approved of the episode's pacing. (; Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages) She noted, "It starts out with action and it does not stop." ()
This episode achieved a Nielsen rating of 5.8 million homes, and a 9% share.  Although the episode was only the joint (with ) seventh most watched episode of Voyagers second season, the installment was voted the most popular episode of the entire season in a contemporaneous fan poll to which Jeri Taylor paid particular attention. ()
Cinefantastique rated this episode 3 out of 4 stars. (Cinefantastique, Vol. 28, No. 4/5, p. 102)
 scored this episode 4 out of 5 stars, defined as "Trill-powered viewing". Additionally, Nikki Harper, a reviewer for the magazine, wrote a positive review of the episode, remarking, "Deadlock' is another classic from the pen of Brannon Braga [….] It's gripping stuff throughout with plenty of shocks along the way, and the Vidiians are at their nastiest." ()
The unauthorized reference book  (p. 112) gives this installment a rating of 7 out of 10.

Apocrypha 
 The events of this episode play a role in the Star Trek: Voyager - String Theory trilogy, where a Nacene infiltrates Voyager by altering the crew's memories and posing as Janeway's sister. Due to Harry Kim and Naomi Wildman being slightly out-of-sync with the rest of the crew (as is established in this episode), they are immune to the intruder's tampering, and can thus perceive the Nacene for what she really is.
 They also play a role in the Echoes book, where the crew stumbles upon a rift in the fabric of space-time that intermittently connects Voyagers universe with the parallel universes of a near-infinite number of other Voyagers. In the book, the destruction of one of the Voyagers in the "Deadlock" episode is explained as actually being a Voyager from a parallel universe, and therefore every other parallel universe visible through the rift is missing a Voyager.
 The Harry Kim who dies (as well as the one who survives) reappears in Star Trek Online. In the mission "Dust to Dust," which takes place in 2410, it is revealed that the Kobali, guided by Jhet'leya (the reanimated Lindsay Ballard) found the deceased Kim and are reanimating him into a Kobali named Keten. He wakes up with most of his original memories and, confused, attempts to contact Voyager—which has returned to the Delta Quadrant on a secret mission. To stop Kim/Keten from blowing Voyagers cover and putting the ship at risk, Jhet'leya, the Harry Kim who survived (now Captain of the ), and the player character talk him down and explain the situation to him. The mission ends with Captain Kim telling Ensign Kim about how he got home and what happened to their shared family. The episode begins with a recreation of Ensign Kim's death from the Voyager episode; Garret Wang provides his likeness and voice. But a generic, forehead-ridgeless female NPC and sound alike are substituted for Roxann Biggs-Dawson.

Video and DVD releases 
 UK VHS release (two-episode tapes, CIC Video): Volume 2.9, 
 As part of the VOY Season 2 DVD collection

Links and references

Guest Stars 
 Nancy Hower as Samantha Wildman
 Simon Billig as Hogan

Co-Stars 
 Bob Clendenin as Vidiian Surgeon
 Ray Proscia as Vidiian Commander
 Keythe Farley as Vidiian #2
 Chris Johnston as Vidiian #1
 Majel Barrett as Computer Voice

Uncredited Co-Stars 
 Steve Carnahan as operations officer
 Tarik Ergin as Ayala
 Heather Ferguson as command officer
 Holiday Freeman as operations officer
 Emily Leibovitch as Naomi Wildman
 Louis Ortiz as Vidiian crewman
 Lou Slaughter as command officer
 John Tampoya as Kashimuro Nozawa

Stunt Double 
 Chester E. Tripp III as stunt double for Simon Billig

References
abdomen; access port; airponic bay; alignment module; alpha-numeric sequencer; analysis; anodyne relay; antimatter; atmosphere; atom; audio communication; authorization code; auxiliary power; auxiliary respirator; baby; back-up power; back-up processors; band pulse; bearing; bio-probe; bio-signature; blanket; boarding party; bone marrow; boy; breast feeding; bulkhead; cabbage; capacitance; carrier wave; celery; cell membrane; cellulose; centimeter; cervical dilation; ; chicken; clavicle; com emission; com frequency carrier; com-link; command functions; computer core; containment field; contraction; cooking; coolant leak; damage; damage control team; damage report; deck; deflector dish; Delta Quadrant; depolarization pulse; dermaline gel; dimension; dinner; disruptor; dizziness; DNA; doubter; egg; emergency encryption code (emergency code); Emergency Medical Hologram; emergency power; emergency resuscitation; energy output; energy weapon; engineering team; environmental control system; EPS conduit; exo-cranial ridge; extraction procedure; face; fatigue; Federation; fetal transport; field emitter; figure of speech; fire suppression system; firstborn; foetal transport; force field; fracture; frequency carrier; fused vertebrate; G-type star (unnamed); G-type star system; ghost image; gigahertz; girl; God; grappling range; green bean; heart; hemocythemia; hemocythemic imbalance; hemo-uterine levels; holodeck; hour; hull; hull breach; hull stress; hyper-thermic charge; imaging array; impulse engines; incisor; incubator; infant; initial; injury; internal bleeding; interspecies abnormality; Intrepid-class decks; Jefferies tube; Kent State University; kidney; kilometer; Kolopak; knowledge; Ktarian; labor; leftovers; logic; magnetic field; magnetize; main power; Mama; maneuvering thrusters; mass; matter; medical system; medical tricorder; medkit; metallurgical analysis; micro-fracture; microcellular scan; millisecond; molecular signature; multispectral analysis; nacelle; name; neck; nerve damage; nursery; nitrogen; offline; organ; osmotic pressure; osmotic pressure therapy; oxygen; pancreatic tissue; paradox; parallel universe; particle; pelvis; pelvic ridge; percent; perimeter alert; Phage; phase discriminator; phase displacement; phase modulation; phase shift; phase variance (phase variant); ; plasma; plasma burn; plasma cloud; plasma drift; plasma drift sector; playground; portable force field generator; pot roast; power conduit; power grid; pregnancy; primary system; prostaglandin; proton burst; psyllium; quantum-level analysis; quantum cohesion; quantum theorist; red alert; replicator; resonance pulse; saying; scales; scan analysis; scratch; second; second degree plasma burns; sector with large plasma drift; security detachment; self-destruct sequence; sensor; sensor array; sensor log; sensor range; Siamese twins; skin; spatial anomaly; spatial fluctuation; spatial flux; spatial rift; spectral frequency; spatial scission; spatial transition; spinal column; stalled; structural integrity; structural integrity grid; subspace band; subspace communication; subspace divergence field (divergence field); subspace field; subspace turbulence; subterfuge; surgery; ; tennis match; theory; thermal array; thoracic contusion; thunderstorm; time; triage; tricorder; turbolift; Tuvok's sons; umbilical separation; uterus; uterine wall; vegetable (aka veggies); Vidiian;  (Vidiian ship/vessel); vision; visual communication; Vulcan; warp coil; warp core; warp engines; weapons array; whistle; yellow; yield

External links 
 
 
 

de:Die Verdopplung
es:Deadlock
fr:Deadlock (épisode)
nl:Deadlock
VOY episodes