Choices? Zimmerman chose to participate in the Neighborhood Watch Program.
Right. Because he was tired of crime in his neighborhood. A perfectly normal reaction, and not only legal, but actively supported by law enforcement.
And Zimmerman choose to arm himself, despite the fact that the Watch Program discouraged its participants from doing so.
Right - such civic groups do not want to be sued into oblivion if a member has an accident while participating. So they take the policy stand that it's not them, but the members themselves that make that decision.
But at the time of the attack, Zimmerman wasn't on watch.
Which doesn't in any way reduce Martin's responsibility for doubling back from his dad's house in order to attack Zimmerman, and then actually committing that assault.
He chose to follow Martin that night.
Right. Because he didn't recognize the person taking an unusual route through the private community while hiding his face. Thought he'd call the police to report it, and take a moment to see where the person was going. Again, a perfectly reasonable response, and in no way illegal.
He chose to disregard police instructions.
See, now you're just lying. Why? The only time he spoke to police was once they arrived on the scene. On his phone call, he was talking to a dispatcher. A dispatcher has no authority to tell anyone to do (or not do) anything, and the dispatcher in question has already testified that no such instructions were given. You've obviously heard the transcript, so you know that the dispatcher remarked that they didn't "need" Zimmerman to follow the suspicious person. The transcript shows no instruction, the dispatcher - who has no authority either way - said that no instructions were given or intended as such.
He chose to get out of the car.
Right - to see where the person was going. Which he did, and then he turned around and walked back towards his truck.
As the one "trained" and armed with deadly force, it was his responsibility to see that the situation didn't escalate out of control.
And it did not get out of control. He observed, he talked to the dispatch on the phone, and he walked back to his truck. Do you consider that to be out of control? The next situation had nothing to do with him - because it involved Martin leaving his destination, and deliberately coming up from behind, having decided he wanted to dish out a beating. That situation had nothing to do with Zimmerman, who was walking the opposite direction.
Personally, I'd characterize Zimmerman as a police officer wannabe.
Which in what way caused Martin to run up behind him and start beating on him?
So he armed himself and continually went out on "patrol", looking for trouble and a chance to be a hero.
Which is you characterization, and appears to be false (in terms of his motivation) by all reports. Regardless, how did his interest in slowing down the rate of crimes in his neighborhood cause Martin to run up behind him and start beating on him?
he allowed the situation to escalate totally out of control
By turning his back on they guy and walking back to his truck?
Faced with an actual confrontation, he panicked and resorted to using deadly force.
No, faced with a punch in the face, a broken nose, and having his head pounded against the sidewalk and being told he was going to die, use his gun once. I supposed you'd have preferred that he allowed Martin to continued bashing his head against the pavement?
End result of Zimmerman's choices? One dead kid.
No, that was the end result of Martin's choice to - having already made it to his dad's house - turn around, make his way back to Zimmerman, and begin a physical assault.