The one thing that has always stopped me from thinking Maura just took off from the crash site (either in a daze or for whatever reason) is the rag from her emergency kit stuffed in the tailpipe. If she was injured and wandered off, I can't imagine her thinking to do that. If she wandered off to find/avoid help, why would she do that?
So if Maura didn't do it, someone else must have .....
There are known knowns; there are things we know we know.
There are known unknowns; there are things we know we don't know.
There are unknown unknowns; there are things we don't know we don't know.
And there are unknown knowns; there are things we don't know we know.