I hear what you are saying but the pump is seized the wheel is totally stuck and it sheered the belt, perhaps part of the belt got lodged in it when it broke?
When it happened i got a really bad smell in the cabin after the belt went followed by black smoke from the rear then i pulled over and opened the bonnet to find the belt had snapped and the alternator was smoking. One i removed th ebelt i was able to drive home (short distance) but my battery isnt great now i have to charge it to turn the car over.
I got the new belt and went fitting it today and noticed the alternator flywheel was fine and the tension was fine but the AC compressor was totally seized.
Some background to this i replaced the solenoid in the AC compressor a while back and it was working great, however i had the solenoid off the car for a week while i was searching for the correct part and i think oil from the compressor leaked out. I was assured this was OK when i got the system re gassed as oil was part of the re-gassing but im suspicious about this and i suspect the lack of oil caused the bearings to seize after a few weeks of use. I also got a new condenser around the same time as that was leaking so its been a bit of a nightmare to say the least...