Question about one scene from "Sounds Like".

In the beginning, there is a scene in that segment where the manager cuts off one guy whom he determines is about to scream obscenities at the client. And, much to that man's dismay, he was right, but I wonder...

Instead of either apologizing or simply persisting that he is innocent, why did he verbally attack the manager in a fit of rage and start screaming obscenities at him, saying "F*ck you, f*ck your ears", call him a "prick" etc, and even more than that, why was he about to swear at the client, what does he, some worker far away, personally care that they may be "dumb" and start to, you know?

And also, did he lose his job as a result or just receive a warning? And why during the process, for example, didn't the manager shout back at him or say "Hey, excuse me, what do you think you're doing?", "Oy, knock it off right now or I will call security or get the police on you", "You're fired asshole, have a nice day" etc?

Or was the whole point of that scene was that somehow at this offset moment, the manager already developed extraordinarily strong hearing abilities and the employee, perhaps rude and disgruntled, maybe even with personal problems, got, in his own way, caught off guard and ego hurt that under those circumstances, he could've heard and predicted what he will do?

Oh and then... He told off ANOTHER employee for actually being more POLITE to the other client because he dared to help a woman with personal problems as well as software issues.