I would tend to make a note of it mentally, and put it in my "tool box" so to speak. If "Tommy" did get taken out, by chance, player and coach are gone and what I heard will probably be in my report. I have talked about coaches and some players myself between myself and other umps. Should I do it? Probably not, but it does happen. Lockeroom rants stay there, but I will have my mental notebook available for the rest of that game. If I feel that someone's safety is in jeapordy, I will pull coach aside, prior to resuming, and let him know about the conversation I happened to have heard while in the lockeroom. There are more times than we care to admit that teams are told we are the reason for their failure. Heck, I cost at teams at least half their games I officiate it seems. Who hasn't had the discussion with your partner about how coach A is a real
pr*ck and will be on a real short leash today? I have had partners actually tell me "I think I'm going to dump someone today" prior to the game. If it happens and I think my partner did it to satisfy his whim, then I will take postgame actions myself.
Giddie up Tangent.
Bottom line, what is said in the lockeroom tends to stay in the lockeroom, until it affects my ability to provide the service I am hired for.