If Scout and Jem are afraid of Boo Radley, why do they run in and out of the Radley place trying to get Boo's attention?
To Jem, Scout and Dill, getting Boo to "come out" has become childish game. It is like children screaming at a horror movie. They talk about being afraid, but they know they are actually safe because they live right next door and can run home if necessary. They don't seem to understand that their game could be hurtful to "Boo" because he can hear them through the windows of his house. Fortunately, they do get his attention because "Boo" actually becomes their protector.