The Things They Carried 
in the chapter "enemies" Lee Strunk and Dave Jensen get into a brutal fist fight over a stolen jack knife. Strunk started going a little crazy and broke his own nose because he was so paranoid that Jensen would eventually hit him back, so he did it himself and inflicted his own injury.
in the chapter "friends" Jensen and Strunk became very close and had made a promise to each other that if one of them got so hurt they would have to be in a wheel chair for the rest of their lives that the other one would take the other persons life. Strunk had stepped on a rigged mortar blowing off his right leg up to his knee. Jensen did not keep his promise because Strunk begged him not to kill him, so Jensen didn't kill him, but he ended up dying anyways.

Response: I think it's crazy the effects that war can have on someone. It can make someone so crazy they break there own nose. I understand why Jensen did not kill him, I could not take someones life especially one of my closest friends. It would be hard to see everything that comes with the war.