I can one up your example, and it was amazing.

About a decade ago I had a kidney transplant. My kidneys were functioning, but at less than 10%. For the next few months everything felt better, but not quite right, so I had a load of tests done.

It turned out that one of the arteries leading to the new kidney had been held closed by a clamp, but hadn't sprung back into shape after the operation was completed. I had to go back into hospital to have a stent fitted to expand the artery back to its normal size.

After the op, I was lying in bed on a ward with a few other guys, having a chat, when I got the sudden urge to pee. I had to use a measured bottle in bed (with the curtains closed), and I'm glad I did, because I wouldn't have made it to the bathroom.

I passed about three or four litres within a few minutes, cleaned my hands, and pretty much passed out. It felt amazing :D