Thought this was about the Comet - guess there were 2 knuckleheads out there putting others at risk. The Comet stunt is even worse.
Yikes - kinda sounds like he'd picked up the throttle or whacked it and then panicked. Sticking it in Neutral or killing ignition would have saved a lot of grief.
If it's a rod-style linkage - as opposed to a cable - there was likely a bind in the system. Or maybe there was insufficient return spring ?
Whatever the actual cause, I would think that would have been tested somewhere safe beforehand. And fixed.