[Botta answers first, his hands empty for now and one resting on his hip. Of the three of them, he's the largest and yet, paradoxically, the least threatening; though he addresses Sheena, he isn't turned toward her as though to present a front, but stands by Yuan, as if a support resource.]

The mana flow needs to be reversed in order to save Sylvarant, but that doesn't necessarily doom Tethe'alla. Our instruments indicate it will take significant time for Tethe'alla to begin its decline. We hope to solve the dual-world problem before that occurs.

[An even and astute interpretation. Kratos nods toward Botta.]

Botta is correct. Immediately after the reversal in mana, both worlds enjoy a period of relative balance which dooms neither. Colette's duty is the Chosen and the need to regenerate Sylvarant are not all that related, except for convenience. Mechanically speaking, her becoming an angel has nothing to do with Tethe'alla's decline.