Ok, so Freddy Gray ran from police, tased his ass and threw him in the wagon. Had to drag him for whatever reason.
He didn't have on a seatbelt. Other prisoner in partitioned can couldn't see him but reportedly said he thought Gray was intentionally trying to hurt himself.
WT's theirys:
1. Gray was injured in the chase as evidenced by his dragging legs. It was either an injury or his being an ass.
2. He purposely tried to hurt himself in the van.
I'm going with 2. He wouldn't have likely made enough noise had he simply fallen to the floor of the van, for the driver to pull over because of the commotion.