MakeShift Challenge: Stay Alive in a Bank Vault: Most Plausible Winning Entry

MakeShift 05: Scott Baker’s Most Plausible Winning Entry
by William Lidwell
July 07, 2006

Scott combined an entertaining narrative with a solid, multi-faceted approach to the problem. Woody comments: “Mr. Baker is one of the few entrants who thought about detecting and planning for lethal levels of C02—-excellent. His estimates were very close to my empirical measures, and I think he would have a good chance of making it out alive. He also correctly concludes that it would be inadvisable to get between me and another vault door, because next time I’m going to make it 72 hours!” Congratulations Scott!

Like the Guide says on the cover: “Don’t Panic”.

Despite being righteously infuriated at being trapped in a bank vault by that dirty rotten [several expletives deleted] Woody for two days with no air, the first prerequisite to survival is to remain calm. Average human activity produces CO2 at the rate of 500ml/minute-–but beating on the vault door while yelling at the bastard that locked me in here will do nothing but increase that rate and decrease my chances of survival. I must retain my Zen-like demeanor, focus on the task at hand, and breathe normally. Slow, steady breaths will ensure a lower CO2 production rate. I’ll flog Woody soundly with a piece of the garden hose specifically selected for this purpose after the door opens–-then he’s buying me a very expensive dinner at the fine dining establishment of my choice. I’m going to be really hungry.

After I get all my preparations complete, I’ll lie down on the table and remain inert. The human body consumes less O2 at rest than when active, so it follows that decreased O2 consumption = decreased CO2 production. CO2 is heavier than air, so up on the table is better than on the floor.

CO2 Removal:

First: a nice, cold drink from the water cooler is in order. Calm my nerves and get together a game plan. After all, there’s no sense getting dehydrated. Hmm…

My overall task is to breathe air that has less than 0.05% CO2. To that end, I’ll cut both connectors off the hose and notch one end of the hose several times about 3” deep to let the hose fit into the vent tube. Woody’s gonna have to buy those construction guys a new hose–-I sure didn’t lock myself in here! Visions of construction guys giving Woody an atomic wedgie dance in my head… focus, FOCUS! Anyway, once I get the hose in the tube far enough, the hose will start to jam, which is good: jam that hose in there good and tight, then tape the opening as best I can to make an airtight seal. Ya gotta love electrical tape. Insert other end of hose into mouth.

Vent tube + garden hose = survival, but breathing in and out through the hose like a snorkel would be a quick way to die (or at least pass out). Despite a total lung volume of about 4 to 6 liters, the tidal volume (amount of air taken in a single breath) of the average human is only about half a liter. The hose + vent tube combined length is likely far too long to allow “snorkeling.” Even if I trimmed the hose short, I’d end up breathing the same air over and over, rapidly increasing the CO2 concentration (and decreasing the O2 level) in the hose and passing out. Assuming I didn’t regain consciousness, I’d just lie there on the floor of the vault until I died from CO2 poisoning.

Important note to self: breathe in through the nose, out through the mouth. A calming technique and lifesaving as well–-bonus.

This vault has electric lights, electrical outlets, and presumably other normally insignificant breaches in the walls and ceilings. Wiring conduits and the like all create teeny tiny gaps that will work just fine to normalize any differences in air pressure caused by exhaling through the hose. Differential pressure should in fact draw fresh air into my Woody-inspired torture chamber, allowing me to get by quite nicely. Since I’m counting on fresh air being drawn in from electrical conduits and other gaps in construction, I’ll take off every cover plate for outlets and switches to increase any airflow, as well as knocking out any blocked knockout holes in the electrical boxes.

The “hose exhalation” solution has an Achilles heel: sleep. I assume that I won’t be able to stay awake for 48 hours–-my max is more like thirty or so, and odds are I won’t remember to breathe in through my nose and out through my mouth while I’m snoring away, dreaming of my revenge on my jailer. Woody must pay…

It’s time to get really creative.

CO2 Total Concentration:

It doesn’t matter how many CO2 molecules are present in the air; as long as the concentration is less than 0.05% by volume (and I’ve got oxygen), I’m going to be okay–-cranky and hungry (couldn’t those construction guys have left me a Snickers bar?), but okay. While I’m sleeping, my respiration will increase the CO2 level in the room since I’m going to take the hose out of my mouth. It’s time to increase the other gases in the room, thereby lowering (or minimizing) the CO2 concentration:

Take the water jug off of the water cooler and top it off from the cooler–a lot of water remains in the cooler reservoir. Set the jug on the floor in the middle of the room. As I get thirsty, I’ll drink out of the cooler.
Make a hole in the jug in the top near the outer diameter, large enough to fit the steel cable.
Feed almost all of the steel cable into the hole in the jug, making sure it lies around the perimeter and not the center. This will be our negative terminal. Where it comes out of the jug, split the cable into strands and pull enough back out of the jug to run the strands to the negative terminals of the transformers.
Have a short fantasy about delivering painful electrical shocks to Woody’s… well, never mind. Gotta focus.
Cut lengths of wire to run from each emergency light’s DC transformer’s positive terminal (used to charge the battery) to the jug. Don’t attach them to the terminals yet. I could use the batteries, but by tapping off the lights, I won’t have to recharge the batteries–-it’ll just keep going. It’s a good thing those guys left a new spool of wire.
Tear apart the phone and get the bottom aluminum plate. Good thing this is an older model phone. Attach said plate to the four lengths of wire, and then immerse the plate in the water without touching the cable. Cut the center opening of the jug bigger if necessary.
Connect the wiring to the positive terminals of the emergency lights.
Watch with pride as bubbles form on the cable and the plate. When I’ve got to pee, I’ve got to remember to raise the positive plate out of the jug first. Adam and Jamie may say that electric current won’t travel up a urine stream, but I’m not gonna risk it!

O2 Concentration:

Huzzah!!! I’ve just made an O2 generator–-oh yeah, H2 too.

The DC from the emergency lights will separate the H2 and O2 molecules from the water. Adding these molecules to the air already in the room will lower the overall concentration of CO2. It should be enough to help get me by while I sleep, considering the minimal contribution I’ve been making to the CO2 levels so far.

Last Resort:

Should the CO2 concentration reach toxic levels–-about 0.08% by volume-–I’ll be able to taste it. At those levels, the CO2 reacts with saliva to form carbonic acid, giving me a nasty taste in my mouth. Should that happen, I’m in dire straits: I’ll go over to my jug, put my nose in the jug and breathe in what should be CO2-free O2 and H2. With the continuous creation of gases in the jug, I should be able to keep inhaled CO2 to a minimum and buy a little more time.


As I stand here in front of the door, my watch counts down the time… 3… (pull the pin–-I’ll tell you in a few seconds) 2… 1… the giant mechanism starts to move. After a solid “THUNK,” the great mass of the door slowly swings wide to reveal my “buddy” Woody, beaming; ever confident that my MacGyver-like brain would overcome his challenge. He may have been a bit impulsive in locking me in here, but I’ve gotta admit that it’s been fun overcoming the obstacles and surviving. So I swing the fire extinguisher nozzle up as I run out of the vault, point it at Woody’s chest and squeeze the trigger. To my delight, Woody’s eyes go wide with shock as the frigid CO2 blasts him dead center! I drop the spent extinguisher, wrap an arm around my tormentor’s neck and give him a hard noogie.

“C’mon you jerk,” I say, “I’m starving, and you’re buying!”

Woody laughs with me as we walk out of the bank in search of sustenance.

It’ll be a while before I let Woody stand between me and a door, though.


> MakeShift 05: Analysis, Commentary, and Winners