Gothic Earth: The Black Hole of Calcutta

My World Between campaign is currently on hold due to shared player and DM fatigue; we've also reached a natural place to pause the game, since some major objectives have been met and the players need to figure out what their next move is within the 01web of conspiracies that enfolds them.

In the meantime, I've started running some loosely-connected stuff in the Ravenloft Gothic Earth setting.  Here's where I'm going with that:

According to Wikipedia: "The Black Hole of Calcutta was a small dungeon in the old Fort William, at Calcutta, India, where troops of the Nawab of Bengal, Siraj ud-Daulah, held British prisoners of war after the capture of the Fort on June 19, 1756."

But what if beneath the cells there was a sub-dungeon...one more in tune with the supernatural expectations of D&D exploration?

Here's my random encounter table for the Black Hole of Calcutta's underdark levels:

d12	Encounter
01	Otyugh
02	Rat swarm (6 HD)
03	Drow expedition (1d4 drow)
04	Mongrelmen squatters (2d6 mongrelmen)
05	Olive slime pack (1d4 slimes)
06	Green slime pack (1d4 slimes)
07	Ghoul scavengers (1d4 ghouls)
08	Ghast outcast
09	Colonial wights (1d2)
10	Wraith
11	Giant bloodworm
12	Troll