First, God will judge us all, George Zimmerman and Trayvon Martin included, for our sins. He is the perfect judge, and His Justice and Mercy are perfect. I always think of them as the heads and tails of a coin. Each is indispensable from the other.
Zimmerman didn't disobey any positive law in getting out of the car. He was just as entitled to walk where he did as Trayvon Martin did. A 911 operator also has no legal authority. Now, should he have done it, using moral reasoning? I don't know. That answer involves his judgment of Martin which apparently was a good one, but based on evidence he didn't have. He wasn't a cop, and called them frequently for poor reasons.
To those who say justice wasn't served, or that we need to forget the laws, or that somehow we should still go after Zimmerman: I direct you to the film A Man for All Seasons. This scene is very appropriate.