well first only have 1 death-guy that's randomly chosen/is the one that won last round, so then some asshat doesn't go off pressing random buttons not waiting for the others
second, for a sci-fi theme, it should be a spaceship, and one of the deaths will cause a part of a wall to fakekill itself and speed bricks aimed towards it, as if the person who died was sucked out of the ship
second should be like last time, but an explosion kills the player as if the ship was under attack.