I am no expert by any means. But, I can only tell you what I would do in this situation. If the perp has a gun, and it's visible, then shoot the bastard as quickly as possible. Draw, aim, fire all your rounds and make them count. Do not think about anything except walking away, alive. On the other hand, if the perp has a knife, or another such non-gun weapon, and you can run away.... then run you butt of and get the hell out of there. In this case, it's not worth drawing your weapon. I think.. and that a big "think" .. I think I would only draw and kill if there was no other choice. You have to remember that they will try to hang you, and most likely succeed, if you had a way out and didn't use it. Only draw your gun if in your mind, there is no other choice. That's just my two cents. One more thing I just thought about. Survival skills not only mean walking out alive in a situation, but also mean covering all your bases in a court of law. We all know what the lawyers will try, in order to hang you. But, if you react from a purely self defense posture, then it's almost impossible to get a jury to find you guilty. So, in summing up on this question, I think if you act like a person who is cornered without any way out, except by deadly force, then that's your best bet. Of course, this is all conjecture and theory. Let's just hope that we are never tested..