I just want to add an alternate strategy. When you come across the two Overseers talking in the courtyard kill the one that goes out toward the main entrance and then go Semblance the one that stops close to the basement window. Go in and immediately up the stairs and past a few more Overseers. At the top of the next staircase is an Overseer looking at a bookcase. Semblance him and then head across the second floor to the stairs. Carefully knock out the witch on the third floor and carry her out of patrol range of the other one. Alternatively, kill them both by using the first as bait. Carefully make your way down the hall and Semblance the witch by the bookshelf so that you can get into the next room and up the stairs. Cardoza is in the room by himself, giving you time to turn off Semblance and cast it on him after your energy recharges. Now just walk out to the waypoint, quickly get out of range of enemies after the cutscene so you're not overwhelmed.