As Nazrim squeezes into the tiny opening, the foul stench is nearly overwhelming. The odor -- or rather, miasma -- has layers to it, almost like peeling back a rotted, festering onion using only one's nostrils.
As expected, there is a tunnel in the ceiling, moving along the top of the main chamber; it looks worked rather than natural, and small orifices let in light at regular intervals. The passage curves away from Nazrim's sight lines after a short distance, but she thinks she can hear scrabbling sounds ahead.