I think in most states an attacker who ends up having to defends has an incomplete self-defense claim. Basically, since they created the situation, their actions cannot be excused simply because it turned bad on them. IIRC (from lawyers' explanations), the incomplete SD is a mitigating factor, rather than an actual legal defense.Those would be the charges, yes... depending on what the states penal code calls such acts. But, the self-defense affirmative defense would still exist to be pushed by the defense.
In the example, I agree with you CB on the probable outcome, though. If a person is the initializing attacker, then it shifts the attacker-defender positions as the Defender gets the upper hand but continues the beat-down, and thus becomes the Aggressor... the now-Defender "could" go to the force multiplier and "could" say it was self-defense affirmative defense in court. The problem is that most judges and especially juries tend to see through that sort of thing and land on the initializing attacker because of the "You shouldn't have started it," thing.
If the force multiplier isn't used, and they get their butt beat by the now-Agressor, they may very well end up winning a ivil suit. It's a tricky dang business.
In the above example witht he student being attacked by a machete-wielding idiot.... granted that it sucks that machete boy was able tofile a suit, but I'd put down a pile of money that the student wins that lawsuit.
And I agree with the countersuit philosophy. If a person is sued for some nonsense thing, you have to pushback. Strategically, it gives you many more options to get out of the suit unscathed (except for lawdog fees).
People are all over the place on these legality questions, and for good reason. The law is an imperfect tool with which to deal with this stuff.
I think the same happens if someone does not intend to "strike the blow" (as in cases of accidental discharge).