You guys reminded me of another one, from many years ago. Obviously, what I did was STUPID!
I had to work on something under a 1959 Chevy, don't remember what. Had a bumper jack & some old house bricks.
Raised one side, put bricks in place to hold it up.
Raised other side with jack.
Crawled underneath.
Dad came home a couple of hours later & found me pinned under the car. I guess I had passed out for a while, due to lack of oxygen.
He and our neighbor got me out with only some cracked ribs & minor scrapes. Could have been a LOT worse.
We figure some of the old bricks crumbled, throwing all the weight onto the bumper jack. The car shifted & the jack popped out.
It's not likely anyone would be using a bumper jack on a MV, but remember to use good strong blocks!
Eric