There is no proof, other than what has been said by Zimmerman's family, that proves GZ had any intention of going back to his car. His own 911 call clearly shows a man following Trayvon. When he says "okay" to LE, he was still clearly in pursuit. You can hear it. Backed up even more by the fact that Zimmerman wanted LE to call HIM back so that he could tell LE where he was. If Zimmerman was going back to his truck, he would have told LE that he would be in his truck and given LE a description of that truck so they could find him if they needed him. That's what they needed him to do... just like they needed him to not follow Trayvon. Zimmerman chose to ignore the advice of LE.
It may not be a demand, but it's common sense that LE was telling Zimmerman not to follow Trayvon. They were on their way. It's their job... not Zimmerman's. Obviously, Zimmerman felt above LE's advice and did his own thing and now a kid is dead because he couldn't comprehend simple instructions.
MOO