Thinking back on it, Hatter realizes how incredibly stupid he nearly was.
He watched her move toward the mirror, not fighting as he should to keep her near. He watched as she was shoved through the Looking Glass, back to where she belonged (not here she doesn't belong here she belongs there far far away from me) without a single "Wait!" or "Not yet!" He turned and left without a backwards glance, walking back to his ransacked, nearly unlivable tea shop, noting that he'd better find something else (legal. Something legal.) to do for a living. He had gone so far as to actually hang up his hat before noticing the jacket in his other hand. Her jacket.
He stared at it for several long moments. Thinking. Remembering. Feeling.
And then he ran back out the door (grabbing his hat first, of course) to the one place he could go, praying that he wasn't completely out of good luck.
When he got there, he was rewarded with the sight of the blond head he both loathed and respected, standing alone by the Looking Glass. Waiting for him.
"Seventeen whole minutes, Hatter. I was getting worried after twelve. Thought I'd have to send a search party."
Hatter only stared at him, silent and wary. Jack gazed back at him for several moments, before he sighed.
"Go. You know she's waiting for you."
Hatter's feet were moving before the words had left the king's mouth, and he had nearly leapt head-first through the mirror before a hand on his shoulder stopped him.
"Tell her...tell her I...hm. Take care of her, Hatter."
With a nod of thanks and confirmation, Hatter stepped into the glass, feeling the whoosh of the trip rush about his ears, but only hearing the joyful screaming of his heart as he rushed to his Alice.
His Alice, who now lay sleeping in their bed, in their apartment, wrapped in his arms with a soft smile on her beautiful dreaming face. He closed his eyes, pressing his lips to her temple and pulling her bare body flush against his. Sleep claimed him, and he dreamt of her.