In prison, Hannibal took off the veil, removed his person suit, unmasked, and showed his true colors. However you want to word it, the man was no longer hiding to blend into polite society and hadn't for years. In the wake of the two of them slaying the Dragon, especially after their first kill together, can you imagine the euphoria Hannibal experienced? He finally had Will to himself, reborn, and in his arms.
No Jack.
No Alana.
... and no Molly Graham.
With Hannibal being the more injured of the two, it's Will who takes the reins to make sure their wounds are treated, to make sure they're safe, and that they are as far away from Jack Crawford's reach as possible. It gives him purpose and provides a distraction from every other complicated thought and feeling he's had since that night on the cliff.
Hannibal is out of practice when it comes to pretending to be "normal." And why should he hide when it's just him and Will as they recover? Hannibal won't put them at risk, of course, not when he finally has so much to cherish and so much to lose.
But he is a bit feral.
Will has a better grasp on it for now, as he had three years of being a family man and all that comes with that. He's never been good at it, but it's passable. I just picture Will easing Hannibal back into life as a free man, much like how he's coaxed stray dogs into his home and hearth. Domestication as much as it's possible with a cannibalistic serial killer.
Whether there is a collar involved is dealer's choice, really.
