There's more than a few janky things about this truck. I'm not entirely sure how I managed it either.

 

One of the characteristics of the LR lock cylinders is as they wear you can remove the key when you should not be able to ie while running or still in drive.

 

It's a good thing you didn't try jumping the terminals on the starter, with it actually in drive. You'd have possibly had some interesting tire tracks across you body. Remember folks, safety first...any time you are under a vehicle...apply the parking brake!

Was helping a buddy once, dropping in a distributor and l told him to just bump the starter to get it to drop in the last bit. He did..and the truck lurched forward and pinned me between the bumper and the work bench. He had disabled the neutral safety switch (for some reason, bad probably)...and it was in drive.