Okay. First - dude, HELP your friend. Don't just stand there thinking, "our friendship is over. Hey, let me go over that lonely corner". Obviously, you guys can't be best friends if you just stand there looking at him. Second, how the heck can that ruin your relationship? You don't even KNOW that kid. Just give yer friend Sal over there some first aid. Done. Third, you should've said something. Honestly.
I'm pretty much glad that kid across the street punched him inside out. Well, I meant if that happened to Miranda. Maybe if this happened to me in reality, I'd be in shock. But it wouldn't necessarily damage my friend's relationship. Yeah, I won't actually go in front of this kid and be like, "little kid, don't do such violent things," or "dude, you're hurting my friend. Punch wars?" but there's no connection between the kid and me in the first place. Besides, a friend that judges you in any way - particularly, in your neighborhood, then that can't be a true friend. I feel as aggravated as ever thinking about this.
Who would you characterize your best friend as? Well, if you have any.