OOC:
Correct, there are no cultists in sight and you are free to move about the room. Each of you definitely feels watched, but as far as you can tell there are no living souls to be seen in this room or beyond the bars.
Amalthea peers down the hall and comes to another bend. Beyond this one is a narrow, five-foot hall lined with prison cells. The cells are doorless, being little more than alcoves with manacles hammered into the stone walls. In one of the middle cells, Amalthea finds a dusty skeleton in a tattered black robe.
Taniwha eyes the relics. The full list contains: a mummified goblin hand, a knife carved from human bone, a dagger with a rat's skull set into the pommel, a varnished green orb with a black slit pupil, a bone aspergillum, a cloak of pale ghoul skin, a desiccated frog lashed to a stick, a bag of bat guano, a hag's bony finger, a wooden miniature figurine of a mummy, an iron pendant with a leering devil face, and a shrunken halfling head. While he doesn't have proficiency in Arcana, Taniwha feels like some of these objects may be quietly magical in nature or be used as components in spells.
The water is harmless albeit dirty. Taniwha can begin to see beyond the portcullis with his darkvision. On the inner wall of the room beyond, just out of reach, is the wheel to raise and lower the portcullis. The room itself is cavernous, and Taniwha's darkvision fails to reach the other side. What he sees are impressions of a huge temple-like space with marble pillars surrounding a central dais.