I was trying to remove the driveshaft from my Torino a while back (can't even remember why anymore). The back end of the car was on ramps in my garage. I removed the U-bolts from the U-joint but the drive shaft wouldn't budge. Since it also wouldn't spin, I realised I left the automatic trans
in park so I get out from under the car and reach in the open window to put it in neutral.
As soon as I move the column shifter to neutral, the car starts rolling down off the ramps. I can't hold the car back and I needed to let go or get caught by the side of the garage door opening. It rolls out the door and down the driveway.
While running after it, the drive shaft falls out (I already removed the U-bolts, remember). I finally catch up to it, jump in and hit the breaks, just barely stopping it before it exited the driveway.
Now I'm in a pickle, the car is at the bottom end of a downward sloping driveway and no drive shaft so I can't just drive it back into the garage. So now I chock the front wheels, use a floor jack and jack stands and complete whatever repairs I had planned and re-install the driveshaft in the driveway near the street.
Should have used the wheel chocks in the first place!