I didn't think that the killing of the terrorists when he rescued the town rang true. I would think that the whole 'saw American soldiers die/No more weapons' thing would have put him off killing. Seems like he would have built additional less lethal weaponry into his armor.
See I took it that he decided that he must make sure the weapns he creates don't fall into the hands of those who would do evil, where before he didnt care as long as he was making weapons.
I don't think he was against killing, just the innocent and the soldiers doing good being killed by his weapons.
