In this chapter, they sign a contract stating that if anything of them went under danger, they would try to en end it, by killing the one who was left wounded
It was a day in October, where Strunk had stepped in a rigged mortar ground, which blew up his leg. By this point, he was at the verge of dying
Jensen had to break the contract not because it was the right thing to do, but because he did not want Strunk to suffer and because he did not want to carry the weight of his life over his shoulders at the time of war. After Strunk is wounded he is taken into a helicopter and dies. It shows that moral does is invalidated during the war.