Once the newcomers meet up with the group searching around the aqueducts, it says the characters can go back through those to escape or go through the heavily guarded corridors of the tower.

I'm assuming the characters will be chased by the undead, and perhaps the guards, regardless which way they go, but am unclear on the situation for taking the corridors. Will the undead discriminate and leave the guards alone because they're on the same side or can ward them off somehow or will the guards be sacrificed to the undead along the way, as well?

Noe is definitely stealing a uniform either way, I just want to get a better picture of the rapidly expanding disaster zone.