If everything you allege about Zim behavior is true, Zim can no use self defense as reason to shoot. It is like I agitated a person and he got mad and swung at me and pinned me to the ground in a fight. While losing and being pummeled, I pulled out my pistol and shot him. The issue is chain of events and when the chain of events were broken. If Zim decided to retreat to his SUV but before he parted and told Martin that the cops were coming and he plans to go back to his SUV and watch them kick his ass. He still has not broken the chain of events because his parting words escalated the situation and not lowered it. On the other hand he tells Martin, fine I don’t want any trouble and I will go back to may SUV and wait for the cops. If Martin felt Zim’s tone of voice was disrespectful and he decided to teach him a lesson, then Martin is now the aggressor and Zim is the defender. In other words depending on the facts, who ends up being the defender can flip between Martin and Zim when the two confronted each other before the fighting starts. My money is no matter what really happened, if Zim has a good lawyer he wil avoid any pitfalls in his statements.
Remember, presuming Zim goes to court, he will have his own lawyer there. Martin will have yet another lawyer from the state’s attorney’s organization who views this as something less than interesting or meaningful.