I have been every guy in this situation at one time or another, I'm pretty sure everyone has for that matter, as I've yet to meet a living saint.
These days I just try to look after myself, and be the player I'd like to play against.
I'll give my team mates (team-team, not game team) a heads up if I see them slacking, and ask that they do the same.
Sometimes I still testosterone rage because I'm a Mongo (esp in CQB), but I always make an effort to give everyone the benefit of the doubt, talk things over between rounds, and calm the fuck down
before even getting to "I shot you!" "No you di'nnt!".
In this sport, we are the masters of our own domain. Serenity now. Serenity now. Serenity now.
Mongo for those unfamiliar: