IMO, I think they just bolted from the car and split up. They probably felt LE was on their tails and would be swarming the area. CN knew the area, but MM and CH did not, IMO. CN ran to his grandparent's home, which was around the corner. I don't think MM and CH had a clue of where they were at the time and I don't think they knew CN's grandparents lived close. At the very least, they didn't know what direction to go. As far as SFG being with them, I'm not sure she was in the car. I tend to doubt it, but since she made calls, her cell phone pings would reveal her whereabouts at the times she made the calls. LE would have that information. So far, I think SFG made those calls to try to track her car down. She may had made arrangements for him to deliver it to her home at a certain time, but he didn't show up.
One question: why would she call CN's relatives after the crash? What would be her intentions for making those calls? To me, it seems as if she was trying to find her car. What are your thoughts?
JMO