This has the revised timeline, and it does show no LE on that floor while shooter was shooting. Early reports had LE huddled by elevator with wounded security guard and some reports even had them engaging with shooter while shooting.
Sorry, that is what I get for thinking early reports are truthful. Or even later ones for that matter.
I guess the hotel disputes this timeline:
http://www.latimes.com/nation/la-na-vegas-shooting-timeline-revised-20171009-story.html
This timeline shows two police officers on the 31st floor at 10:12 with shots still being fired until 10:15.
They arrived on the 32nd at 10:17.
I wonder if the shooter somehow saw them arriving (by camera?) and killed himself then?