Should we be surprised that Ammon wounds the king in the arm? The only thing we should be surprised about is that Ammon didn't cut the whole thing off! However, Ammon is always thinking like a missionary. How would it look if he was forever held responsible for amputating the arm of the highest of the Lamanite kings? He can't permanently disfigure him, especially because Lamoni's father is going to be a key future investigator. One of the first rules of missionary work is not to cut off the arms of your investigators.