I did not say ...."why should he"
You said that in post #95. So what are you talking about? What is your point.
The point of my post is that in my opinion the conditions simply changed as referable to a life-threatening circumstance. If the shooter did feel his threat had been neutralized, he no longer has a circumstance which require a lethal response. Others see it differently, from what I read on this post.
And had he allowed them to live, you don’t think he would be terrorized and possibly hunted down and killed by the gang of criminals these teens probably call their “friends”? He’d be living in a 24/7 fear of retaliation had they lived, mark my words. I think for his own life, he did the right thing by taking out the criminal/enemy.