John is nervous
Katie saw that John was worried about where Charlie would go for the two nights that he was out of town for his bachelor party. Katie was going to have her party in the city, which meant that she would still be at their apartment. She told John that Charlie could be here with her.
But as much as John cared about Katie, he knew that she was careless and didn’t want anything to happen to Charlie. Katie told him not to worry about it and that she would keep an eye on him for the two nights he was gone. He agreed after thinking it over.