I realize this is a bit off the wall, but I wonder if she could have been hit by one of the trucks and instead of calling ambulance etc. he/they just pulled her in the vehicle and took off.
They wouldn't want to waste time doing all the reports and interviews especially if the driver was to blame.
I don't think that's "off the wall" at all. I think at this point, that seems most likely what happened to her. And it DOES happen - I've heard it before and actually I think that's probably what happened to Rachel Cooke. So yeah, I agree with you.
The part I don't understand is the shoe. I'd like to know what kind of shoe, exactly, it is. Because I can't even take off my jogging shoes except to unlace them and remove them with my hands - I can't pull them off using one foot against the other the way you can remove looser shoes.