This mission requires that Imperial players move 4 neutral character tokens around a maze-like corridor path to get them into a prison cell on the opposite side of the map. A large separated platform is set up around the center of the far side, so the prisoners must get close to it. Models can move up a ladder into the space, where they get overwatch on the whole board especially longer range heroes like Loku (duh), Fenn, and Mak. In my case, Loku and MHD-19 got up top and basically became impossible to kill while Jyn and Ghaarkan made advancing both the prisoners AND the imperials nearly impossible.
The problem: There is no obvious limit on which characters can go up the ladder as long as they are small figures. And this means that the rebels can simply boost the prisoners up the ladder, at which point they are nearly impossible to retrieve in a timely fashion. And the Rebels can easily block the prisoners to force them to stop at or near the ladders. If the Rebels position right, even chasing a prisoner up the ladder is useless because they will drop down and immediately be forced back by the Rebels again. Or they'll be positioned to simply block Imperial models from getting up and through.
Is this mission winnable as Imps, or should I chalk this up as an intentionally easy Rebel mission?
BTW open groups were HK droid Elites, E-Web Elite, and Officer Elite. I think I probably should have replaced the E-Web with something else, maybe an Elite Probe Droid or even an ATST.