The editing in this scene is AMAZING.
This conversation, their looks, their closeness was already so intense, but they also blurred Will and Hannibal’s face, except for their eyes.
It makes this scene EVEN MORE INTENSE. We are reminded that they’re losing themselves in each other and of course, in their eyes.
Remember that this scene was right after Will visited Molly and her son in the hospital, Will is furious about what Hannibal has done, but still, he cannot save himself from Hannibal's eyes, and still finds the excitement and also the relieve in those very eyes. Also, just look at them... Deep down Will knows that he will never be able to save himself from Hannibal and he's right. And Hannibal... He is literally dying for Will. He already gave his freedom for Will, and ready to do more. I think he would never kill a child, but he was ready to cause one for Will, "Don't you crave change, Will?". It was both revenge, and an attempt to win Will back. It's a sick feeling like Molly said, but when it's Hannibal, it always has to be something extreme because his feelings are always extreme when it's about Will.
(Wanted to add, not something that I could ever justify, but it's something that I try to understand.)