You walk around the curved hallway, reach the middle and stop to turn around and look at a marvelously blank part of the inner wall of the hall. This part of the castle never stops feeling darker for some reason, the curves on always reminding you that you are in a perfectly round part of the building.

With your back to the lounge door, you see two doors to the left of you and a surprisingly straight stairway, leading up and a door to the right.

You've by now decided most definitely that you can continue down the hall in either direction, and it'll just send you back to the other side of the circular hall.