The big circular area is meant to be an auditorium, the giant quarter-circles are a sloping series of pews facing the center stage at the bottom, the ceiling above a spherical dome. I drew and redrew this, trying to make the circles perfect. I even scanned in a simple pencil copy missing the circle and tried to put a circle onto the map using GIMP and it just didn't line up correctly. I've been stressing out about this map for weeks now. It wasn't until I started drawing the pews for this final map that I realized I should have started with the circle and built the rest of the level around it. I understand why there are few circular areas in old modules now, they're a bitch to draw!
I'm not going to redraw it. At least, not until after I playtest it. For now, I'm going to finish drawing the entrance.