I don't think i've ever felt so harrowed by an interview with a murderer before. I felt less creeped out by the talking head Nazi leaders in World at War.
You're seeing him in his element, he's still in the act really, you can see the thrill he gets from so casually accepting why people could accuse him of these things. "Sure! i can see why they'd think that, because [...tells the truth]". Seeing this guy get a buzz from skirting so close to the line of the truth after so much natural bullshit. He feels untouchable. Who can blame him after that Texas trial? He almost seems bored of his freedom and just wants to push it, like when he mills around the porch of his estranged brother's flat (that sequence is kind of hilarious in a really grisly, dark fashion btw. Sipping his Orange Julius. lol.)
Watching his body language fail to comply with his firm, unflappable denial when confronted with the envelope was just...one of the most fascinating things i've ever seen. He's never been in that vulnerable and tight a spot before, no lawyers, no spin, no rehearsal. His central nervous system can't deal with that lack of control.
Do you think he knew the mic was on in the bathroom? It'd happened once before, and he's a smart cookie. Could be a desperate attempt to sound crazy to try for an insanity plea in the future. Chilling as fuck regardless.