Going down doesn't seem to be a problem; there's a ramp passage a short distance away, but on the way there there's a pulley-drop cart system for bringing ore up quickly; special angled carts on a circular track up and down a steep incline between the third and fourth levels.  It's the kind of thing used to move ore before they get the full mine-cart tracks laid, and since the fourth level is well-established at this time, it's comparatively disused, the carts recycled for use between the fifth and the start of the sixth level.  It does allow for a fast descent, but isn't easy for a way back up.<br/><br/>Koh maintains his stealthy creeping, but surreptitiously lets both of the others know he's still there before they move out.<br/><br/>Closing the ramp passage has changed the airflow qualities of the mine, and the air finds its new pathways pretty quickly.  Something about the new flow-ways travels across a drill hole or something and creates a constant, low-pitched quavering moan.  The darkness is negotiable, but this deep, everything is very chilly, and there's a dampness condensing on the walls.  What with the river right close by, the water table in the area is high, and the mines are well, well below it.  That has its effect.<br/><br/>The map shows the possible ways down as well as up; it's just a matter of where they want to start for.