The drifting tunnel continues upwards for an uncomfortable distance and after about five minutes you're tired from the climb. As the torch begins to breathe it's last, giving about three minutes warning, you come across a place in the tunnel that seems to have been shifted by an earthquake (which are fairly common in the area) ages ago. The difference is perhaps six inches, with the tunnel above you simply shifted to the left and some stones in the walls and ceilings broken.
It seems to be stable, however; the dust on the floor suggests the shift happened at least years ago. However, more recent, something has emerged from the rift and crawled upwards along the tunnel, leaving a trail of grease behind it about three feet wide.
Here is an image of the room, after Sofia's discovery: