Scout had already gotten closer to the Radley house than she had ever planned when the tire in which she was riding rolled onto the Radley's front steps. When her head finally cleared, she realized that she was staring right at the steps that led the dreaded Radley porch. She ran as fast as she could back to Jem and Dill, and Jem questioned her about why she didn't retrieve the tire, which was now in the Radley yard. Jem summoned the courage to bring it back himself. Scout does not mention it at the time, but following Atticus' admonition to stop playing their game, she decided that this was a second good reason to stop. She had heard laughter coming from inside the Radley house while she was on the step, and she must have realized that it was probably coming from Boo.
In Chapter 4, Scout makes a "smart" remark directed at Jem accusing him of believing in "Hot Steams." Jem gets upset at his sister and decides to take revenge by pushing her in the tire as hard as he can. Scout rolls toward the Radley house at a high speed and ends up crashing into the Radley porch. Scout flies out of the tire feeling dizzy and nauseated from the turbulent ride. When Scout realizes that she is in the Radley yard, she panics and runs away from the house as fast as she can without grabbing the tire. Jem courageously runs into the Radley yard and retrieves the tire. After successfully grabbing the tire, Jem says, "I swear, Scout, sometimes you act so much like a girl it's mortifyin'" (Lee 50). Scout mentions that there was more to it than Jem knew, but decided not to tell him. What Scout is referring to was the laughter that she heard coming from inside the Radley home. After hearing the laughter, Scout believes that Boo Radley is still alive, which is one of the main reasons she is reluctant to partake in the game "One Man's Family."
In chapter four in To Kill a Mockingbird, Scout, Jem and Dill are trying to think of something to do. Summer has come once again and the children are trying to find a way to entertain themselves. Jem says that he will push Scout in the tire. Jem pushes her really hard and she goes rolling right into the Radley yard. Scout is stunned by the jolt and doesn't realize at first where she is, then the yelling from Jem shakes her out of it and she runs out of the yard.
Jem, Dill and Scout start playing a game about Boo. Scout isn't really into it, but she doesn't want to be left out, so she goes along with it. When Atticus comes along and catches the children, he is very upset with them. He warns them to stop playing the game and to leave the Radleys alone. Scout is glad her father came along.
Atticus's arrival was the second reason I wanted to quit the game. The first reason happened the day I rolled into the Radley front yard. Through all the head-shaking, quelling of nausea and Jem-yelling, I had heard another sound, so low I could not have heard it from the sidewalk. Someone inside the house was laughing.
When this happened, Scout begins to realize that Boo is actually watching them. The children have spent so much time trying to find a way to see Boo, but Boo is the one who is watching them. Jem and Scout should be very thankful that Boo is watching them, in the near future they are going to need him.