The white eats away at everything, until there's no scenery left at all, no solid ground, although the invisible plane on which they stand doesn't shift beneath them. But that nothingness never touches Sephiroth, even when Cloud himself feels as if he might disappear. (As if he might just like to, in the face of this impossible revelation.) And that is confirmation nearly as clear as the general's word.

"Then- This is really happening?"

Unlikely is being entirely too kind to the situation at hand. Just as much, Cloud would rather know what could possibly have brought someone like Sephiroth into his (mind) presence. Of all people, a lowly cadet - and his dreams?

"It doesn't make sense."