I have not followed nearly all the articles on this (I will try to get caught up), but I was following it “live” during the hours after the shootings — in one of the earliest articles there was reference to a bellman observing lots of glass crashing down outside the hotel. They might not have known instantly which floor it came from, but they may have known within seconds that a window had been smashed.
It would have been hundreds of pounds of glass. Somewhere I saw that those huge windows weigh 600 lbs each but I don’t know. That would have been a tremendous smash on the ground if any hotel staff were indeed nearby to observe it.
I saw that. Bellman heard glass, then shots.