If you want my honest opinion, just mind your own business and stay in your lane, and I mean that in the most respectful way possible. If it is something that is going to put someone's safety/well-being at risk, absolutely tell someone. But to me, there is absolutely no point in putting this much effort into a situation that has nothing to do with you or your success. And anyway, karma never misses its opportunity
P.S. I'm sure you are a very fine, respectful individual, but to be this "gunner" kind of person is the best way for you to make enemies. Nobody likes a tattle tale