You continue walking towards the supposed source of the green glow.
As you walk, you notice a few things. First, the air starts to get drier and colder. Now this is to be expected of dark, chasms like this, but the air seems to have a negative amount of hydration in it. Strange, I know. Second thing you notice about the mausoleum as you approach some point, is that the ground, walls, and the assumed ceiling all seem to transition materials from a basic stone, usually found in mausoleums, to a type of stone you would recognize from the underground.
The third and final thing you notice as you close in is an eerie noise. It sounds like the death of a birthing calamity. Whatever it is, you don't necessarily like it.