I haven't thought this through much and can't really figure out how either. One possibility is those windows open partially with a tilt (since it wasn't broken) so it picked up different reflection? Or just off a random car or business?
The Luxor and TheHotel would be the closest properties I think. Neither at an obvious angle.
I'll use this as an example ...the only thing I could think of is some ( maybe most ) windows at The Mirage open slightly ...
it almost works like a slot window where you unlock it and push out, but it only opens about 4-6 inches
so if I was on a higher floor with a rifle or whatever at night, there goes your reflection
it's the only thing I can think of right now.
But i would think if the cops saw this video or had reports on it, we would have heard about a 2nd shooter