Mary said "thats disgusting".

Possibly.

It IS how large animals, cattle, sheep, pigs, and horses are usually put
down. I have seen cattle put down this way, and the gun was put to
their head, fired, and they instantly dropped, dead. From start to
finish, the whole thing was over in a couple of seconds. So.....?

But, as i said earlier, I'd heard/read a couple of vets say it was the
most humane, instantaneous, and how they would euthanize their own pets.
That's why I inquired as to whether or not anyone here had had a pet
euthanized that way.

I'm not advocating this; just mentioning it as another possibility.