At the Mandalay Bay it would already take one more than enough time just to get to the 32nd floor. On top of that, with a concert going on in the immediate vicinity, traffic could have been horrendous, possibly impacting law enforcements arrival on the scene.  This guy had enough ammo to take out more than he did. I wouldn't be surprised if this guy had something to do with "black ops" in his not so distant past. We all need to be thankful for the efforts of our emergency responders, without them the numbers would have been higher.