Paul and Keith had no idea what was going on. All they knew was what they were seeing right in front of them and what they were experiencing.
They could both see the incisions on the other's heads. They could both hear the claims coming from the other, that it wasn't their wives, but instead each now had the body of their friend's wife. They could feel their new forms, look down and see their familiar forms in an unfamiliar way, and they could see that they were in some sort of recovery room, though past the curtains they could tell nothing else of their surroundings. Past all of this, they had no idea what had happened.
As they tried to make a bit of sense, they heard footsteps. Maybe this person had some answers. As the footsteps got closer, they heard a deep, maniacal laugh and both reacted, Paul putting his hands to his now more-ample chest and Keith steadying his friend. Whatever this person had to say, neither one of them doubted it was good.