Underfoot Depths zone in location?

No accurate info online, and I've spent hours looking ingame.

Is it in SF or The Hole, and where?

The western door inside the Hole says "Underfoot Depths" if you right click it.

Now that I am walkin around here...just to be clear, in Paineel right click purply transporter and go to the Hole. Then in the room with 3 doors it is the W door. It is a really confusing area, as the eastern door says "Enter the Hole" and the southern door says "Descend into the Hole."

Thank you very much Elyria! You're a gem.