had a somewhat similar experience a few years ago
we were at church after service shooting the breeze and one of the guys had turned his truck on to let it warm up
one of his kids was playing in the truck as kids do
he was in the front, in the back, jumping up at down, probably 3 years old or so
at one point the kid made his way back to the front seat, and started jumping again
he had one hand on the steering wheel and the other hand on the gear selector
sure enough, at one point he jumped up, and on the way down managed to slam the truck in gear
the truck, still running, lunged forward and started off towards the church building
luckily the front windows was down and i happened to be close enough by i could dive into the cab through the drivers door and slam her in park before it hit anything
now, if you can get a hold of Paul Harvey, you might hear the rest of the story, but thats where i end, on a high note