When The Hound let his guard down and told the face story to Arya and then The Mountain gets re-introduced I was almost certain that somehow The Hound would get word of the trial fight and booked it to fight him for Tyrion, then right when I was thinking that, that's when Obyren walked into Tyrion's cell and I remembered about he and The Mountain's history. That's when it hit me of what's going to happen and I was like, "Fuuuuuuuuuuck this is gonna get good."