I am leaning toward LE having a solid lead as a reason for the silence lately. Why else would there be silence, like you said, what would they have to lose at this point unless they are in the midst of something major. Maybe wishful thinking on my part but my gut feeling tells me otherwise.
The rear of the store is very key since I believe he did go out the back and ran toward the front and one of those vehicles picked him up. I do not believe he got into his own car. Number 1, it takes too much time to start the car, put it into gear and drive away. Not to mention what if his car gets blocked in. Someone was already in a car waiting for him to come around the front and that car was already running and in drive.
Like I said before, he had to had lookouts in the parking lot. Someone was making him aware of what was going on outside the store in case any LE vehicles came close to the store, or maybe even more customers. I don't believe it was an accident that he took them to the room where the back door was. He wanted to be as close to that door as possible.
He very well could be dead, maybe he was just one player in a larger operation who became a liability once his description was made public.