Here is something that I found very interesting - from Dr. Payne's class. He told us that the military has an extremely complex and organized set of rules and regulations about killing. You see, for those who have to kill, they can't just make up a couple of reductios and run off from there. They have to do it all the time, and so they have ot have precision as to when one can kill and when not.
The point is that when killing is not necessary, they don't do it.
He told us a very interesting story. His son in law is an Army Ranger. A man broke into his house and he heard him. Payne said that he presumed he would have shot him and killed him. But the Ranger's answer was, it was not that simple. He needed to take into account a myriad of factors (and do it in a split second - that is what separates a trained killer/warrior from a wannabe). "Like what?" Payne said. "If he was armed, if he knew how to use the gun, what he wanted, could he be incapacitated instead of killed, what the danger was, etc...."
So what happened?
The Ranger turned on the light, with his gun pointed right at the man. The man saw him, and likely the guns and military paraphenalia on the walls and dropped the gun and put his hands up. I have no doubt that if he had not done that right away, the Ranger would have shot him.
My point? Self-defense is right, but we need to be very sober about killing. I have to admit that I thought very differently about the issue, and my own bombast before hearing that story. That was a very good class that day.