Zimmerman was clearly stalking the kid
Do you know that nearly 4 minutes passed between when TM passed the "T" intersection and when the fight occured in nearly the same spot? 4 minutes. Better story would be that GZ set up a tree stand at the T intersection hoping TM would return for a pack skittles he dropped and then GZ had the drop on him... yeah maybe that happened. GZ probably misjudged the landing and hit his nose on the small tree nearby. Then he was too fat to get up and was screaming for help. When the polite young TM tried to help him up GZ pulled him down into the clinch in order to sexually assult young TM. TM was soo stunned he couldn't scream help on his own. Finally breaking away from the cluthes of the pervert GZ, TM, still the polite forgiving young child, decided to reach down once more to help up GZ who was still screaming for help. But it was just a trap. GZ quickly drew his gun and fired on young, innocent TM.
That's how it likely played out...