It makes no sense that LEO would place the ladder in a narrow alley way that is partially hidden by tall shrubbery.
I’m not doubting your guess but I’m just looking at the overall moment
Well it would give quicker access to both the left and right buildings, and also it goes to a flat roof rather than one with a slight pitch, and the height of the ladder just gets there, where the roof of the main building I think is a little bit higher. At this point I think crooks used the ac unit on the other side of the building next to another joining corridor that had a lower roof than the main buildings. The guy in my post 98, was not crooks but a guy alerting LE to someone being on the roof. In this video of crooks on the roof, but the LE guy and the guy in my post 98 can be seen again, LE closer to the beginning and the other guy sitting on left of video towards the end. That is not crooks, I believe that this guy told the cops someone was on the building. Take a look at this video of crooks on the building, in it you can also see the cop moving to the right, and also towards the end you can see the guy in this photo sitting down on the left side. This guy probably helped save Trump in a small way.
https://news.sky.com/video/trump-rally-shooting-moment-gunman-takes-position-on-roof-minutes-before-attack-13178272