1) A classmate in grade 11 was offended by my subjected-headed, color-coded, neatly hand-printed chemistry class notes (of which I was, admittedly, inordinately proud) so he came to my desk and slashed through them with his six-inch knife. Having put a ridiculous amount of effort into those notes (being dysgraphic, "neatly printed" implies insane levels of commitment, but I had been told that was the only way to learn Chemistry) I had placed my hand down over my notes to protect them. I hadn't believed he would actually cut through my hand, he hadn't believed I'd be stupid enough to put my hand down in front of a moving knife blade.
So that happened. When the principal drove me to the UofA hospital with my finger hanging by a thread, the resident in the hospital took one look at it and said, "oh wow, you're in luck" and disappeared. A short time later a group of about 11 doctors showed up and sewed it back up. Turns out, the worlds leading expert on reattachment was there from England giving a seminar to the doctors at the hospital, and they all poured into my cubicle while he sewed me up. "Now here's where a lot of guys make a mistake. You have to reattach the tendon with this technique, not that one" or some such. (This was 50 years ago or so, so can't get the wording exact.) Slightly surprised that wasnt considered an operating-room operation, but I was awake and they just did it right there on the gurney in the ER.
Still have a pretty cool scar on that finger, but otherwise, types fine.
Classmate was incredibly apologetic and I never identified him because I had recognized it had been an accident (adolescent males, eh?) but pretty sure that would be his only knife fight story too.
2) My third or fourth day as a substitute teacher, I arrived in that day's assigned junior high to find two males facing off against each other holding knives. Being inexperienced and not knowing that one should not insert oneself into a knife fight I said, "Right! What's all this then?" in my best Monty Python voice. I put my hand out for the knives. Which they both fell over themselves to give me, having realized before I had arrived that they did not want to have a knife fight, but had no idea how to back down with everyone else watching this standoff. "Oh damn! If this guy had made me give him my knife, you'd be dead, man!" "Oh yeah? You would have been dead if this guy had made me give him my knife!" Had either of them been vaguely serious, I would have had a very short teaching career. The punchline though is that when I phoned down to the principal's office to report having taken knives off two students and asking for a little backup here, the VP replied, "Is that 8F?" I allowed how it had in fact been 8F. "Well,can it wait until after lunch?" "Knives," I repeated. "I had to confiscate knives from two students in a knife fight." "Yeah, that's 8F. I'll see you after lunch." I chose not to return to that school.
3) A young protege of mine found himself holding a knife facing another guy holding a knife on a dark street with no one else around and the other guy was apparently quite serious about this being an ACTUAL knife fight. My protege, realizing he was about to die, made the unexpected move of stabbing himself in the stomach. His opponent went, "The F***?!" and took off. My protege dragged himself to the bus stop where the driver called an ambulance. When the police asked him, who did this to you, he said, "I stabbed myself" and the police said, "look, we know you don't want to testify against the other guy, but the bus driver saw the fight." "No, I actually stabbed myself" "Don't worry, we won't ask you to testify, but he's going down for this." etc. Not a strategy I'd recommend, but he did survive.
Image Credit: http://www.clipartpanda.com/clipart_images/hand-with-knife-clipart-3568526