If so, this constituted assault with a deadly weapon, and Trayvon would have been fully justified in defending himself with physical force. If he'd had a gun, he would have been justified in shooting his assailant. Since he didn't, he was fully justified in attending himself the best he could.
the assailant can stop the fight, achieve clear physical separation, and state clearly an intent to cease fighting.
Fairly obviously this point is not reached until the victim of assault gets control of the weapon.
I have no idea whatsoever if that is what happened, but it is certainly possible and does not conflict with any of the known facts, AFAIK.
Fairly obviously this point is not reached until the victim of assault gets control of the weapon.
Umm. No. First, both parties could lost control of the weapon (it could drop from a bridge into the water below). Second, the original assailant could pull the trigger several times, with no shots fired, then holster the weapon and fight for several minutes before announcing he was giving up, and physically separating, and turning away. At that point, he's still liable for the original assault, but attacking him can be deemed another assault under the law. Or - he can even eject the magazine, announce that he has ceased fighting, physical separated, walk a mile away, and turn himself in at the police station. He's still liable for his assault. However, if you get into your car, drive, find him at the station, and strike him an iron pipe from behind, you can be liable for another assault. At some point, there's a separation of space and time such that one assault stops and a new one occurs. Get it?
I can make up these parades of horribles all day long, but let's get back to my original point. I was simply pointing out that, as a matter of law, your statement that someone who commits an assault cannot claim self-defense. At common law, there are facts under which an assailant can claim self-defense against what is deemed at law to be a subsequent, additional assault. And by some statutes - in Florida, notably, Florida Statutes 776.041 under the Stand Your Ground Act of 1995 - the person who is the initial assailant can use deadly force or force likely to cause great bodily harm against the party the assailant initially assaulted under certain circumstances.
I don't have to speculate about Zimmerman pulling a gun. I'm just correcting an unintentional misstatement of the law.