You want it to sound like it is a modern gladiator fight. It's not.
Sure they go in there to win and your three ways are how they win. But any fool that thinks he will step in the ring and knock the other person out and win the fight every time is an idiot.
Boxing is a sport with rules limiting bad behavior/actions. There are less rules broken in boxing then football and soccer.
You might want to go find out how many fatalities have happened due to those three sports then we can discuss the dangers.
You are hung up on the prize fights, which do have a few incidents(far fewer then other sports), instead of boxing as a whole. Go to a boxing gym and watch those who box. Tell them they are there only to "inflict injury" on others.
P.S. There are four ways for scoring a boxing match. Anyone can get together and slug it out. That isn't boxing.