I can not imagine me at that age standing and watching this let alone participating.
the only question would be get involved directly in an attempt to stop it or go get help.
even that question would not have been based on my own safety (I was too stupid to know I could die at the time) it would have been more pragmatic.... ie could I actually stop it as one person or would I need help (police, friends, school officials whatever)
About a year ago my wife and I went to a late movie. Afterwards (about 2AM) we were driving home and entering the interstate when we saw a very heated argument between a man and a woman along the side of the road. He was grabbing her and things looked like they were headed south. I couldn't stop because I was already on the ramp.
I drove to the next exit, swung around and went back. I didn't know what I would find. My wife had her cell ready to call the police if need be and I was going to just ask if everything was ok. Pretty risky, but seemed like the right thing to do.
When we got back the dude ran and left the girl. She would not accept a ride from us but asked if we would wait until her friend could get there.
I made a point to discus it with my son and daughter.
I try to mind my own business but my ample gut has a way of telling me whats right.