I’ve seen posts taking the contents of Hannibal’s letter to Will in s3 literally–it is not! Hannibal is not advising Will to stay away from crime scenes for his sake. It’s a taunt and a challenge. He knows Will won’t sit back and do nothing, and he knows this is bad for Will. His intention is to provoke and bully: “Hey Will, I know you need to do this thing that’s very important to you. You want to save these families. I know you have a soft spot for families. I know you won’t deny Jack. And we both know how dangerous this is going to be for you; It’s dark on the other side and madness is waiting :)” It invokes a sense of doom and inevitability. There is only madness waiting for you, Will, and we both know it.