Walter: Every day... for the past 25 years... I tried to imagine what you would like as a man... my son. But I don't deserve this. I don't deserve you. I realize now this was my punishment. You were sent to tempt me, to see if I would repeat the mistakes of the past. You shouldn't be here.
Peter: Walter, no.
Walter: Wherever you came from, however you got here, it doesn't matter. I can't help you.
Peter: Walter, you don't understand.
Walter: I tried to help a boy, a version of my son, 25 years ago. But that boy was never my son... and neither are you.