Trigger Game

Imagine yourself looking for foods after nuclear war. You find foods at last but you are not alone. There are 2 more just like you. Killing both of them sounds impossible seeing as how they are also holding their guns. But, Killing just one and sharing foods sounds doable and quite safe. Problem is who will die? To make it worse, What if you meet your "friends" next time? Will you have to kill them too? or, Will they just kill you instead?