Right. So.
The map is a spaceship. There are airlocks on either side of the cabin. Players can knock each other out, and throw ko'ed players into the airlock the jettison them into space (where they'll freeze) every so often the ship will malfunction, as it does when it's being piloted by hyper violent animals, and gravity will weaken (like black hole lab) or other weird bizarre space things. Maybe an alien of some kind will sometimes reach in the open airlock to grab at players.