I don't like just jumping to conclusions..
In the videos I've seen of 4th floor flashing, I am trying to determine if the flashing continues even when gun fire doesn't, and it is hard to tell, because if you watch the video, the flashing continues even after the gun fire stops.. Light travels faster than sound, so if there were any kind of delay, the light flash would stop first, and then you would hear the sound (not the other way around)..

Is it possible for some one to find a normal video of that same hotel at night time and see if there is actually a blinky light on the building like that or not?.. I don't want to jump to thinking the shooter is on 4th floor when the whole time it is just a damn light blinking..