I'll take a beating, if somebody's man enough to give it. If he's willing to leave it at that, fine. If the fight's over, and he keeps stomping, I'll unload on him.
No, you won't. If you think the fight is over, and he keeps stomping, he will most likely keep stomping until he gets tired of doing so. He will most likely not let you unload on him.
Most folks do not know the outcome of a fight, or even the result of the next punch or kick or stab, or where it is coming from. Your best chance of staying safe is, if verbal de-escalation is impossible, advancing to the rear. If that won't work, you should escalate not to the next higher level, but to the least higher level which will clearly control the situation. For most folks, this is probably drawing the gun. For some situations, it is firing the gun. For some situations, it may be soaking the aggressor with OC.
The difference between cops and non-cops is that cops don't always feel they have the option to retreat. Non-cops should usually (absent the family) feel that they have this option. Other than that, the rules are the same - no rules; just make sure you go home tonight.
Some LEO's may butt in and tell about all the rules they have to follow. I am sure they will be telling the truth, and they certainly have my sympathy, but they belong to the wrong department. There are departments where the rule is that the cop goes home, and the perp chooses his own fate.
Regardless, that is the rule for non-LEO. Sorting it out later is what lawyers are for. Just make sure that you don't use or threaten lethal force unless a reasonable man (you) would be in fear of his life, and then shut up until your lawyer teaches you how to get all the reasonable people on the jury to understand your reasonable fear for your life.
And stay the hell out of bars and bad neighborhoods.