...and I'm pretty sure any bottle with a sufficient charge becomes an instant missile if you knock the valve assembly off.
Oh yeah, I've seen it. We were constructing a new building many moons ago (late 70's) for a new steel fabricating shop.
There was a bank on one side of the building so it was built up with concrete blocks to form a wall/foundation for setting the metal walls on.
Well, someone had removed the safety cover on a large 02 cylinder and before it got secured, it got knocked over, the valve snapped off and it was like a missile, traveling across the floor and blowing completely through the block wall and buried itself in the dirt outside.
It's probably still there, as the wall got repaired and the tank wasn't removed.