There are some morbid shipwreck stories where the starving survivors drifting in a lifeboat draw straws to decide who to will die so that the others will have something to eat. There’s even a term for it. “The custom of the sea”. In fact, I remember a recent thread about it 
In a small space like this, I doubt that anyone would be able to kill someone else unless it was a group decision. No one is going to sit by just a few inches away and not do anything.