Will’s realisation does not help him, of course, because the show is too dark for that. In the final scene, in Baltimore Hospital for the Criminally Insane, at the end of the corridor on the left, we find not Hannibal Lecter incarcerated, but Will, paralleling where Abel Gideon has been and Hannibal will eventually be.
What allows Will to ‘see’ Hannibal — in all his horror as Will’s black stag hallucination — is that Hannibal has been too profligate. Will could have believed that he had killed Abigail and eaten her eye because there is a horrible, albeit gruesome, logic to it, and because he knows that he is sick. But he cannot believe that he has killed Cassie Boyle, Marissa or Dr Sutcliffe because he believes he was not sick (enough) when those murders happened, so the evidence planted by Hannibal and convincing to Jack Crawford’s team must be wrong.
That illness and his fear — he has already told us how much he fears that one day he will be locked up in this hospital — have actually made him stronger. His composure when confronted with Hannibal in the final scene makes Hannibal himself smile. Dancy’s intonation when he says, ‘Hello, Dr Lecter,’ is absolutely perfect, striking the note of greeting Hannibal — the real Hannibal — for the first time, and he does not shy from him, but stands full square in front of him and stares.
I’m not sure whether Hannibal is sad about having had to incarcerate Will in the same way as he was sad for having to kill Abigail. On the one hand, we could argue that Hannibal has ‘lost’ a friend, at least physically, at least in the sense that Will no longer feels warmly towards him. But I think that assumption mistakes the meaning of ‘friend’ for Hannibal. His interaction with Dr Du Maurier, the way that she eats with him and holds his secrets close to her chest, suggests that the importance for Hannibal is having his darkness accepted. This is what he hoped that Abigail could offer him, and he was disappointed when she failed to have the breadth and depth of mind to do so. Therefore, Will has only just become Hannibal’s friend, although of course I doubt he would see it that way!
Finally, as an off-hand comment, this show is usually stunning, but I haven’t always been quite convinced by the black stag that haunts Will. I think this episode, where Hannibal is depicted as the stag, is a clever idea, but visually I didn’t quite buy it.