I don't think he returned to his vehicle but rather he continued to follow the kid. The incident happened in the back yard of a townhouse, didn't it?
You are incorrect. Zimmerman started to chase Martin after Martin started to run. The dispatcher at the SFD asked if he was pursuing, he said yes, dispatcher said you don't need to do that, Zimmerman said okay. Stopped and stated to dispatcher that he didn't know where Martin was. Listen to entire Zimmerman call to SFD. You can find a link in post #33 on this thread.
You are speculating. I don’t have a map of the gated community to determine the veracity of Zimmerman’s statement. Fortunately, the police do have such knowledge and based on the physical evidence and testimony, they felt that they could not arrest Zimmerman. Those are the facts.