Somewhere along the route that was available to them, Sephiroth felt on the inside of his trench-coat a bit to make sure the weight of his Slate was still present. There was no reason it shouldn't be, but the louder the rumbling got the clearer it became -just as Finn said- that they might not actually be alone down here. Somehow.

Machinery or monster; it didn't matter. It felt that he was going to need to switch Swordmaster into his active job slot in order to be better prepared. After all in Illusionist, he only had the initial skill in at this point. Sephiroth didn't yet take the Slate out of his pocket though, instead focusing on keeping his perception sharp as they proceeded, and listening to what he could make of others' comments over the growing din.