Vietnam as a grunt (a foot soldier). One time on patrol they got ambushed and almost everyone in his group was killed and he was wounded. As the battle died down he was wounded bad enough that he couldn't escape so he laid on the ground and faked being dead. A North Vietnamese soldier rolled him over to look at him and, the guy I was teaching, shot the Vietnamese soldier, instantly killing him. He teared up telling me and my companion the story. He said it really hit home when he went through the Viet soldier's wallet and saw pictures of his family.

War is terrible. I hope that man is now at peace with himself.