There are several other indicators that make me wonder if he had expected someone else to be there with him too.
The photo below shows a weapon and a clip staged near the main entrance to the suite (location indicated by the blue circle in the layout to the right). This spot is located at the 6 O'Clock position, his rear, behind Paddock's firing position on the crowd.
Paddock did fire at security, but not with this weapon (no clip in the weapon, clip is still up on the counter). Paddock was already dead by the time the SWAT team breached the room. Makes you wonder why he would set up such a position if his plan all along was to just stick a pistol into his mouth.
Another indicator is the cart set up outside the room. Even if the receipt in this article showing two meals (with two Pepsis) were ordered isn't true, the cart shows at least 7 plates and two water bottles.
Two windows broken out. Why? Would shifting from one window to the other really offer that much of a significant difference in firing positions, particularly from that high up and that far away? Doesn't seem like it.
Of course, this is all purely speculation on my behalf, but it seems to me Paddock expected someone else there to help fire onto the crowd, then possibly fall back to cover his rear while he continued firing....only that person never showed up.