Disclaimer: Things I don't own besides Alice: the Nile...and I'm not swimming in it either.
Author's Note: I'm apparently extending my visit just a tad, but JUST a tad, I'm still not setting up shop in this fandom. *mutters* Must stop reading Alice fanfic, makes muse, well, be muse.
He had all the time in the world to follow her. With a time difference of one week to an hour, he could afford to take a moment to think, he could wander for a few hours to ponder his decision, he had the opportunity to take a few days to rest up from their little adventure, and there was nothing stopping him from taking a few weeks to set his affairs in order. He can see Charlie off, back to the forest and the Kingdom of the Knights, maybe find a minute to check on the resistance and their Great Library refugees, while he's at it he can spend some time poking the Jabberwocky at the Dodo over the fact that the 'blood-sucking carpetbagger' had done more to save Wonderland than he ever did. If he feels like it, he can even insert himself into the new King's busy schedule, much to both of their displeasure he is sure, to give himself the chance to learn all that he might need to know.
Given that the clocks on the other side of the Looking Glass are practically standing still in comparison to Wonderland, he has no shortage of time to get himself prepped and ready for her world before Alice even has a chance to miss him.
Not that Hatter does any of this, of course.
No, he's spent a whole minute dancing about in agitation since that stupid Suit had rudely hauled her away and shoved her through the mirror and that's quite long enough, thanks. The man barely has time to step back from the Looking Glass in satisfaction before there is a blur of movement, and Hatter decides that since they are all about throwing people through the glass around here, he might as well throw himself through.
It means, of course, that they are going to arrive almost at the same instant, what with the time lag and all, but he's followed her this far, makes no sense not to go the rest of the way.
Besides, she's been gone a whole sixty-three seconds now, he misses her.