I. Hate. This. Mission!
A new runner named Cobra decided to glitch hunt this game. One of the things he found, is that some edges in the jailbreak mission have weird collision, which makes Spidey float in the air. Those edges are right above where the end cutscene takes place at.
I later found that you can web-crawl on something by holding RB (wall crawling button) without moving the control stick. If you do it against the corner of the edge, you may clip under ther ceiling. Sometimes you clip immediately, other times you need to climb down (like what happened in the video).
Inside the room, some walls have collision that doesn't match the textures. Obviously, they never thought you'd be able to be there, so they didn't put too much care to do that.
Unfortunately, this doesn't trigger the cutscene, it seems like you have to break the prison bars and the wall that leads to this room. Doesn't matter if you're just starting the mission or broke all 4 generator by riding on Rhino.
Still, this is a cool find nonetheless, I just hoped to find something to skip this awful mission.