You've had experience with something like this before? [ Yako sounds intrigued, like she'd like to ask more about that, though this also likely isn't the best time to get into it, at least beyond what's similar to the present situation. ]

If we aren't entirely anchored through this world except through the mirrors we came through... that would certainly explain why it's easier for us to get pulled into those shared dreams. But they still had to have come into existence somehow, right?