Towards the end of Level 6...
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There is a teleporter that keeps cycling through 4 locations. One of these is a 1x1 room with a face and a button. When you click the button it releases poisonous gas. I have not figured out if that opens up another area or not.
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There is a scroll that says Westmost. I have not found where to place this.
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There is an alcove with nothing in it. There is no clues nearby, but I'm wondering if something happens if you put something specific there. This could be nothing, as there are empty alcoves in numerous places further into the dungeon.