"And then the three gangsters start runnimg...running after the Great Detective!" (p.30)
David encountered the trouble in the real life and he becomes a brave person like in his daydreaming. And he didn't daydream after that. So I think that he canged this scene.
David often daydreams and he is a brave person in his daydreaming. We can be any kind of person in our daydreaming. So it allows us to change feeling or to escape from reality. I also often daydream. When I fail in my part-time job or I have troubles, daydreaming makes me feel better. It is not good to daydream too much, but it helps us in many ways.
If I were David, I can’t help Jack because he was bullying David. So, I think that David is a very good person and I want to be a person like him.