Perhaps The security guard is in on the plot.
Hard to believe Paddock only hit him one time and in the leg with as much weaponry as he had. What kind of uniforms do security guards wear?
Maybe a much larger attack was planned and Paddock just went for it.
Or maybe the security guard shot Paddock, then was the shooter himself.
There you go, that's some good thinking. Best theory I've heard in a while. I'll go with that until it's proved wrong. I'm halfway serious you know.
The shooter’s clothing and skin was covered with powder from all the shooting. The guard would be the same if he had fired hundreds of rounds. Powder literally embeds into clothing and skin when you shoot that much.
Assuming this new timeline is true, I am starting to think the bigger picture plan went out the window once the security guard heard the drilling and the gunman had to shoot. Once that happened he quickly put his plan into action and started shooting. He rushed the attack because he knew he was on the verge of getting caught or killed.
This could make sense in any scenario. If he is the lone gunman he only was able to complete part of his plan in a smaller window. If others are involved his rush to shoot might have foiled say a driver who was going to park that car with explosives by the venue or by the fuel tanks.