This level revolves around a central outdoor area, with several areas that are connected to it. Still no heavy resistance.
Upon reaching the circular courtyard, go inside the square structure located in its center. Flip the switch inside to open three pathways leading out of the courtyard. Go through the eastern opening, where there are three rusty metal "fences" with chaingunners behind them. Lower the one to the north, then open the wall with the inverted cross design on it. Flip the switch in the room behind, then return to the previous room. The inverted cross wall opposite the one you entered the switch room from has opened; lower the fence in front of it, and follow the pathway beyond up to a ledge overlooking the courtyard.
At the south end of the map, beyond the red skull barrier, is a room with a lowering lift upon which is a shotgun. Open the wall directly across from the lift to get a soul sphere.