Article below is from the Daily Mail. Hard to believe there is more in this article from a British tabloid than any other source I have found. If the article is correct, police dispatch did not call SWAT till 10:24pm (16 minutes after the first calls were received about a shooter.)
SWAT at hotel and starts to move up to 32 floor at 10:37.
44 minutes later, they breach at 11:21pm. 44 minutes to climb 32 flights of stairs?
http://www.dailymail.co.uk/news/article-4945322/Vet-wants-know-cops-took-long-stop-shooter.html
(This is weird too, Vegas likely is working with Shot Spotter, a gunshot detection tech which is able to send the specific location of gunfire to local police dispatch within 45 seconds of the shot being fired. Shot spotter has not said if their technology is in Vegas, but they are in almost 90 cities across the US, pretty good odds they are there.)