Trayvon no longer was protected by stand your ground when he ran away and came back in contact with Zimmerman.
You don't KNOW that to be the case.
This is the one REAL unknown at this point. And there's no witness, not even Zimmerman, that can say that Martin escaped and then returned to fight
Zimmerman said he lost Martin. Martin could have been anywhere at that point. Hiding behin something waiting for Zimmerman to go away. But when Zimmerman started back for his car, he became a threat again as he approached the hiding place.
It's all conjecture about that portion of the story.
But think about everything else. It all makes sense until THAT moment. From both sides, you can see the misunderstanding building to something. Zimmermans story makes sense until THAT point. A kid runs away, then what? He takes some magic pill to get courage and jumps the guy who was just chasing him? Really?
But, if Trayvon felt he was in danger, then and only then, does his alleged attack on Zimmerman make sense.
Think about it man. Set aside all the stupid shit we've heard about racism or the stand your ground law, and really put yourself in the situation. This is about two people, both feeling threatened by the other. So how does it play out? What makes sense? And what is crazy?
If you've run in fear from your assailant and escaped, do you return to confront him? Or do you attack only when you feel you've been cornered?
Fight or flight. One of those conditions had already been met. We don't switch over to the other unless the first choice failed.