This is one of my favorites. I love your ending lines, comparing the Old Testament law of "a life for a life" with FMA's Law of Equivalant Exchange. I also liked the attention to detail, such as how Mustang came by his cigarette that had been made in Ishbal.
You've also done a wonderful job of showing Mustang suffering from the beginnings of combat stress reaction while still keeping him in character. Overall, a very nice job.