I suppose preparing for it isn't a bad idea..but considering other options isn't a bad idea either.

[She then thinks for a moment, trying to remember.]

A little bit. If I remember correctly, he said that it was because of two reasons. The first was because of Anima's activation, that would destroy the Lower Domain and the Collective Unconscious..and the second reason was because of the souls that rejected the universe and became Gnosis. When too many of them are produced, the Lower Domain will collapse.

..That is, if I'm remembering it correctly.