With the shadows having fled down the tunnel, what is revealed is a clearly constructed structure, one that has been hollowed out of earth and stone for a purpose. While not overly large, such a tunnel could support the reasonable movement of necessaries at speed, provided they were willing to walk closely together, or had otherwise strong coordination. The floor of the tunnel has been deliberately roughened to provide better grip on what could otherwise become a slippery stone surface, should it become overly moist, and shows less dust than did the open cavern floor, suggesting that at least some of what had passed through that space had done so via this tunnel.
Deeper down the tunnel, at the very edge of where the carried lights reach, there roiled another patch of dark energy, equally as unpleasant as the first. Given the nature of the shadows, and the fact that they fled rather than dissipating after chilling the Chanwyr, they are clearly not natural phenomena. Also visible slightly closer was a dark spot in the stone making up the side of the tunnel that suggested either a branch, or perhaps just a ridge in the stone structure.