Penn and Teller Fool Us: Kostya Kimlat Makes Penn Mad
Adam Rifkin stashed this in Magic!
This post seems to have it figured out:
I saw his move, he is a master card mechanic. He counted and held many MANY clusters until the last moment, and de-homogenized the deck in one move at 4:05-4:07, flipping the incorrectly facing cards to the right direction while keeping the chosen cards in the opposite facing orientation Penn notices a move and it's why he groans... because the absolute skill involved is baffling from P&T's vantage this move would be almost impossible to see (probably why he invited them on stage), and 99.9% of the audience are normal joes with no card manipulation experience....
Redditor vonmeth explains:
When he is going through the deck to allow Penn and Teller to place their chosen cards back in the deck, he is actually at that point sorting the deck into to 'halves'. No reason to keep going through the deck and displaying each card after Penn has put his card.
You can then see when he flips one 'half' the deck of the cards so they are both now facing the correct way (when Penn starts to get mad at 4:04 in the video).
Further elaboration if you need it.
Watch at .25 speed starting at 3:56.
9 of Diamonds is showing.
3 face down cards are shoved away. Notice how they are not put next to the 9 of Diamonds. It is all face up cards showing in his right hand (except the 'top' card, which he uses to obscure this fact. This obscuring face down card is later transitioned to to the bottom deck when he does that flip later on.)
He pauses briefly on the 4th face down card (Penn's card) because he is reorienting where Penn's card is going. You can see that it doesn't disappear to the bottom of the deck like the other face down cards, but is actually shoved up top next to the 9 of Spades and all the other face up cards. You can see him briefly have to reorient it so it doesn't get shoved down like the other face down cards.
6 of Spades is now showing, and it doesn't get shoved down to the bottom of the deck like the face down cards. 5 of Spades then put up to top next to the 6 of Spades.
2 face down cards then go to the bottom of the deck.
Queen of Hearts is put next to the 5 of Spades now. This is where he messed up the biggest. He stops briefly, pulls back and puts it back in. He seems to have put it down to the bottom instead of the top.