After he slipped on the high heels, something caught his attention out of the corner of his eye. He turned and saw what it was.
It was the stone! He had completely forgotten about it. Right before he got snatched by the kidnappers, he had put the stone in his pocket. And now after he had stripped out of his clothes to put the dress on, the stone must have fallen out of his pocket and onto the floor.
After checking to make sure no one saw him (the door had a small window it, so the kidnappers could check on him, without having to open the door), Jon grabbed the stone.
Then, quickly thinking of something to wish for, he said "I wish ..."
