Yeah... it would have happened a lot sooner had someone in the place been ready to shoot back.
The security guard got there within ten minutes. Paddock had jammed the stairway doors, otherwise he would have gotten their sooner. He saw the guard on his surveillance camera and shot him through the door, then shot himself because there were no more shots after the guard was shot.
The guard stopped it just by showing up. Paddock was a total coward, obviously, and he didn’t want to take a chance on engaging anyone who could shoot back.
The media has not mentioned this and sadly, people on FR have apparently not thought of it. Almost no one could shoot back, even if they had arms. The chances of hitting some of the other hotel rooms would have been very high, endangering the occupants, who were innocent. I haven't heard anyone talk about that. Only sharpshooters with the right equipment could have engaged him.
Amateurs with rifles could easily have hit windows the gunman was not using. Nice pipe dream though.