Based on the initial stroll, Ignatius isn't on the first floor. It's mostly empty rooms and mechanical storage down here. The entire place seems like it was under a rushed state of construction.

Looking up, he can see through the outer rim of floor... and then nothing, for a large chunk in the middle of the floor above them. Something about the floor there is blocking his sight, and all he sees is black.

Though, what he can't see may be just as telling, here.