Okay, so when I was in your situation and seeing a kid get stomped in the head, I remember also being very upset. It is troubling to see. Worse yet, the stomper was Tjayden, a skinhead who ruled the school in a reign of terror and was very hansome. My boyfriend at the time said we had to get out of there (it was at a party and we were doing some unsavory things, so we didn't want to be there when the cops came). I said no, we gotta get the guy. We argued about it a bit and then heard sirens. The skinhead troupe ran off, as did everyone else. I made my bf help me pick up the stompee and throw him in the back of the truck. His head was fucked up and swollen, and he'd been stabbed in the knee and was bleeding all over me. He was so disoriented he thought the blood was mine. I told my bf we'd bring him down the street to the Fire Dept and dump him off. And so we did. I never had to pull a gun on anyone.
About a year later, by bf and I ran into the guy. He said thanks--and he looked good as new.
And nobody got shot.
Nobody forfeited their right to live (which, by the way, you don't get to decide b/c last time I checked, you weren't God).
And nobody got shot.
So get a grip already you Seattle pussy.
If I thought the guy getting stomped was in actual danger of being maimed or killed, and I had a gone I'd shoot - but try to knock them off their feet, not kill.