In some instances don't you just have to get into the mix when it was not your problem to begin with?

Is there just some instances where you should be a butinsky? If at work there was “Tony” and “Derek” who was smitten with “Tina”, which she knows and plays both against the middle as most believe they see it.. Neither one wants to listen to anything about that gal is trouble so they are working hard to get her attention. In a heated argument Derek says he had sex with Tina and attempts to rub it in Tony’s face. Tony calls Derek a trick saying he got a BJ from Tina with out having to spend as much on gifts, dinners, etc as Derek did and got it quicker. They decide they would step to the back parking lot and “have a talk” to settle the matter. After 12 to 15 minutes Tony walks through the door with a knot on his forehead and 3 minutes later in comes Derek who looks as if a bus hit him, he has a fat lip, a mouse under his eye, a bloody nose and a cut on his brow. Everyone looks at each other but no one says anything. The Super see Derek and rumor says Derek told the super he was attacked by a bee on a smoke break and tripped and fell over a pile of pipes. Derek is sent to the ER. The next day it is discovered Derek has a fractured eye socket and a broken nose. Management wants him to file a worker’s comp. Derek don’t want to but is getting pushed hard to do it do everyone’s butt is covered. Derek feels if he keeps stonewalling really negative things will come his way from upstairs. No one wants to be the leak or the rat but to keep Derek from being talked into committing fraud (because the super and such don’t know what really happened) would that be one of those times where you have to get into the mix that wasn’t your cake to bake?