i think you are going in the right direction. some sort of device.
why would they lock a person in a closet?
I haven't watched the episode a second time yet but, has anyone here ever been on a sub? EVERY door is the size of a closet door on a sub...
I think we can safely say it's a "room" of some sort. Does this (possible) person locked in a room on a ship scenario remind anyone else of a similar situation? When the freighter had the communications officer, Minkowski, quarantined for "going crazy"?