"Fools rush in where angels fear to tread"...what does your brain tell you?

I was walking down a well-lit central area in a large city awhile ago. A friend was with me and we were walking back to the hotel instead of taking the subway, after dinner.
There were numbers of people out walking as it was a beautiful Spring evening. It was truly relaxing and wonderful to be without snow!
My friend and I had not seen each other since school, where we had slogged through required classes together, laughing the whole way. It was nice to meet up and compare life’s differing pathways we’ve taken. I still couldn’t believe that she had had three kids! I would not have predicted that!
We approached a street corner while on the main thoroughfare. There were two streets that submerged at a point about 40 sidewalk paving blocks away, to the left, as both joined to come to form this side street entrance onto the main thoroughfare, where we were on the curb, about to cross.
We were beginning to step down, when we heard some horrific noise coming from one of those converging streets. Someone was getting the hell beat out of them.
My friend and I were horrified to see a group of late-teens to beginning-twenties in a circle of about seven, not counting the guy they had ahold of. Two had the victim bent double, arms held behind his back, while the older, bigger kid was kicking him in the face- as in: swing his leg back then forward and up, smashing the toe of his shoe/boot in the restrained guy’s face!
I had never seen such cruelty before. If they had continued, I knew this young guy would be dead.
Here’s where the differences of my friend and I gave us two different reactions to this situation.
I was on the right, holding my handbag over my shoulder with my coat over my arm, same side. My friend, walking on the left, carrying the same, was saying something, as I looked past her, I saw all of this struggle taking place.
I was stunned, and turned to go towards the struggle down a little ways, all while I scream-yelled: HEY!!!
I shrugged off my bag and thrust it and my coat at my friend, as I started down the street, yelling something about ‘what the gosh-darn were they doing, and who in blue-blazes did they think they were….’ (Only using a whole lot more profanity than I put down here, I guess)
They all stopped at my first shrill scream that turned into a HEY!!!!! and turned around- except the guy who was so messed up that when the two stooges dropped him in surprise, he went straight to the ground and didn’t move. They all had shocked looks on their faces when they see a woman- all five foot and short inches, storming towards them yelling at the top of her lungs, like a banshee. The other dweebs took off (probably glad that someone else was getting picked on, instead of them) and the three left just stared at me with their mouths open.
My friend snapped out of her shock at what had happened to the pleasant conversation and whirled around to look at the whole scene- mouth open like she’d seen Santa Claus. She grabbed my flung coat and bag, and rushed after me. Two purses, two coats, and she still grabbed hold of my upper arm and swung me around, back towards the main street. I started trying to shrug her off to go back, and she loudly hissed at me: Leave it!!!
“But they’re gonna kill that guy!!!” as I tried to swing us back around- because she wouldn’t let go of my arm and it was close to getting wrenched outta socket.
She stopped long enough to foist my stuff back in my arms and then yanked me on across the street to continue on down the crowded sidewalk.
No one else on the busy walkway broke stride.

Who’s reaction was correct?

(Oh, this was an agreed ‘no phones’ dinner-rule that evening because we wanted to talk without all the interruptions our phones seemed to be doing all day.)