The soldier who stepped on the bomb towards the end
He was the one walking with the other guy, trying to find the American soldier. He accidentally stepped on the ground grenade or rigged bomb, or whatever it was. The other guy could not really help him. so he walked off? I don't blame him, what could he do, really? However, if it was me who had stepped on the bomb on accident, I would immediately ignite it, just to get the satisfaction of killing the person who refused to at least try to help me.
"Duh. You're the idiot. Not me."