He's anticipating this, now. He went through it with Papyrus, and that was like a million times worse. No reason he can't handle this like a pro. He's always been more hands off with Alphys anyway.

He spreads his hands illustratively.

"This... is going to be confusing," he predicts, though his tone and expression are still light and casual. "Speaking generously... I think we're several screwed timelines removed, at this point."

He isn't cautious about mentioning timelines to her because for once he can be pretty sure that she'll get it - both as a scientist and also as a nerd.