They decided it was time for Jon to get back to his body.
Jon first put Karyn back in her body, and then took Samantha and put her in her room to give himself a little time.
As he swapped back to himself, he awoke refreshed, and gained all of the knowledge he should have from school, and had the stone in his hand.
He decided that he needed to make a few quick wishes to help things so he wished ...