In his mad dash to leave his room, Jon accidentally bumped into his mother Jane and immediately swapped bodies with her, meaning that his "essence" hopped into her body.
"Sorry, Mom," Jon saw his body say, and then watched as it briskly walked down the hall and down the stairs, leaving Jon to stand in the hallway.
He looked down at himself and saw that he was in his mom's body. "Weird," he said, noticing that he also had his mom's voice.
Now, if Jon was in his mom's body, then who was in Jon's? In the story, Charlie started out as someone else and not himself. But it seemed like in this case that Jon's body was Jon, mentally. Almost as if a copy of Jon was made and was forced to move into his mom's body.
Wanting to see what the "left-over" Jon was up to, he decided to follow him.
