Jim spent most of the trip in near darkness, since Rebecca chose to put him in her purse. He kept on feeling the other contents of her purse either bumping into him or poking him. Her keys were the worst.
Figuring that Rebecca couldn't see him now, he decided to change back. But then he reconsidered. While he no longer wanted to be a cellphone, he didn't want anyone to know about his new ability. They might think he was a freak or something. And Rebecca would surely tell the whole school and half the neighborhood if she saw him growing out of her purse. No, he'd have to wait until he was totally alone.
In the meantime, he pondered what could have happened to Rick. He knew that he was planning to mess with his sister and Jim was fine with that, but that was back when he thought Rick would become invisible, not turn into an inanimate object. What if he turned into a plant, or a chair ... or what if he turned into food or something? Suddenly, Jim became increasingly concerned for his friend.
Little did he know, Rick was feeling the same thing about him.