There used to be a way for attackers to flank the right side by going around back and up a staircase... this staircase is now missing. I don't think that attackers are in any way OP in this map, so I don't see why it would have been removed on purpose. It is a very vertical map which always favors defenders. Not only that, but various other scene objects seem moved around, as seen in one of the snapshots where a tower (or is that the missing staircase?) is horizontally placed in a small hallway.
Missing Stairs:
Glitched Tower in Hallway:
