The amount of hyperbole in many of the responses are truly surprising
While I agree there needs to be compensation, I stand in the camp that thinks a free night is adequate, whether in the form of a refund or points to give a free night in the future to an equivalent property.
Structure integrity?!
A piece of drywall came off, this has nothing to do with structural integrity of the building.
As far as wondering if the rest of the ceiling would come down... Water leaks from the bathroom above likely waterlogged the drywall and caused it to come apart. The likelihood of this occurring anywhere in the actual bedroom is nearly zero.
If one takes a shower for 15 minutes on average, he had a 1 in 96 chance to be in the shower when the material fell. So, amazingly lucky to not get injured when the likelihood of being in the shower at the time being near 1%? I think he would have been amazingly unlucky to have been injured by it.
There are many things in life that occur where you "could" have been in harm's way. But, when harm hasn't occurred, one doesn't go around expecting compensation as if harm had occurred.
When my car has a mechanical issue I don't tell the car dealer that I could have crashed because of it and they owe me. When I flew in the Boeing 787, I didn't go back and tell them that I could have died because of the battery issue, so they owe me. One could clearly state that I could have been in harm's way with both of those scenarios.
I am not making light of the OP's experience. I, too, would have been upset by being woken up at 2 AM and having to switch rooms. For that I would expect compensation. It is just a matter of what each individual feels is adequate compensation. But, lets not make up untruths about structure integrity and being amazingly lucky in order to make a mountain out of a hill.