When Wain destroyed part of the stone slab, he jumped down. Teresa also followed him. Unlike Wain, Teresa could not feel the aura of the World of Darkness at such a distance. Wain could feel strange energy only because the necessary component to unlock the second form was there.
Wain didn't know how, but his skill, Nameless King's Forms, somehow interacted with the Seal of Darkness. This was unexpected, but it was one big plus for Wain.
When Wain went downstairs, he was in the middle of a strange room. It didn't look abandoned or dirty. It was perfectly clean. But, the furnishings inside were strange. It was something like a hospital room.
"What is this place?" Teresa muttered. She had already joined Wain.
"Decided to come down? I thought you'd run off with your tail between your legs." Smirking, Wain said.
"I never run away. I just found this place very interesting, that's all." Said Teresa.