Simply because Toph doesn't know, just because she's not the person she'll be in the future, it doesn't change that this Toph is the seed for all things -- that what she is today accounts for all that will be between them. Or the fact that Toph will love her daughter absolutely, fiercely.

For the moment wide, pale eyes whisk towards Lin at the words, startled. As the dream ends and the link between them ends, Lin will be able to see them -- and Toph herself, confused, mouth opening to speak.

But it's too late. The world is already slipping away between them. It shreds away, leaving the landscape of gray.

Toph is nowhere to be seen.