Serenity, do you by any chance study martial arts? Reason I ask is that kick you delivered to the mugger's ribs kinda sounds like a back kick. Very powerful kick you can deliver with your back to an assailant with him coming in on you. Grabbing a rail and kicking from this position would possibly work to get someone off you and could break ribs, etc. Then get the heck out of there fast. All that part sounds like you did the right thing. Leaving before they got there would have been best. Sometimes that's not an option though.
I'm using the term "you" now to refer to anyone. It may be possible you could get in trouble if you hurt these guys and it was discovered (if you were sued) you study martial arts. I don't know. I have heard that if more than one attacker is involved, you can use any force necessary to defend yourself, so if you did accidentally kill someone in that situation it seems a reasonable case of self defense. There again if the kick or punch killed someone, that is different than pulling out a knife or gun and using that. Your age would likely be taken into account and whether you were physically able to run or fight.
Anyway, now we know what a Hawaiian punch is. Fortunately you weren't hurt. At your age, if you left them unconscious and got the heck out of there, that would be understandable. Dealing with two is different than dealing with one. I would have gotten out of there asap.
That little bit of hesitation is very common, and is why he got the punch in on you. This is not the time to think. I'd say you did what you could after that without having to use the knife. Good for you.
Hehe, I knew a fellow whose mom gave him a pistol to start carrying with him to school when he was 15. She told him, This was for self protection to be carried all the time. She was a school teacher and knew what some high schools were like. I don't think he ever carried it to school though. He was too smart to do that and probably didn't have too anyway.
Les