Mirror Universe Encounter
Mirror Universe Encounter was one of the holopod simulations presented by Shari yn Yem during the drills she conducted aboard the  in 2381. According to Yem, the simulation was based on the experiences of various other Starfleet crews.

In the simulation, the occupant was placed aboard a fictionalized mirror universe version of their starship, populated with mirror versions of their crew members, and tasked with escaping back to the prime universe.

Ensign Beckett Mariner was among those that took the simulation. Despite bluffing her way past , , and , Mariner was exposed by  when she gave the Terran salute with her left hand, as the   was right handed. The prime universe Mariner was immediately apprehended by  and , then shocked by Boimler using his agonizer.

Unknown to the crew, Yem had tampered with the holo-program so that the entire crew would fail. ()

Characters 

 

Holographic programs