You climb down the shaft. The vertical shaft is a mix of crumbling earth and ancient stone, and centipedes and other insects cover the walls like living decorations. The long descent takes you deeper into the bowels of Dorasharn Tower. Soon, the shaft begins to angle, and by bracing yourself you can actually walk along one of the surfaces. Farther still, and the shaft becomes a tunnel, and the footing is no longer difficult to maintain or treacherous.
The tunnel eventually opens onto a vast chamber, though it emerges about six feet above the floor. You can't see the distant walls in the darkness, and the ruins of nearby walls and building appear as deep shadows in the eternal tower night, but you can feel the change in air currents and pressure that indicate a large open space in front of you.