Everyone outside:
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Daiya can feel a presence on the other side of the wall, roughly where the pounding is coming from, although it is difficult to tell through the constant vibration of the moving wall. One would assume that it is Grimmgang.

Trunk's spider clambers upward, avoiding the occasional moving part, and makes its way carefully through the passages above. These appear much more promising - they are clearly currently in operation, for one, and far more extensive. Once above, in fact, it is much easier to move, at least for the small spider, and it manages to reach the apparent end of the mechanisms, or at least the parts accessible, at what you judge to be roughly the other end of the hallway, on its western side. There is something vaguely resembling a control panel here, although it faces the wall and does not appear accessible from this angle.