I would say that the following three people events help to make Montag change to being a rebel.
- Clarisse McClellan. She makes Montag sort of take stock of his life and realize that he was not in love, was not liking his life, etc.
- The old lady who burns herself up. She made him think that there must be something to books if she was willing to kill herself over them.
- Millie almost kills herself by accident. This makes him realize that her life is empty and that she doesn't care about him or their life together.
Two other important events and characters that influence Montag to change in Bradbury's Fahrenheit 451are Montag's first meeting with Faber, which the reader is told occurred before the opening of the novel, and Montag's encounter with the mechanical hound.
Faber leaves enough of an impression on Montag that Montag remembers him, and when Montag wants to learn to comprehend what he reads he knows to call Faber.
The mechanical hound spooks Montag, and demonstrates that the society is just not right. It's threatening actions toward Montag place Montag as an outsider, even at the fire station. The hound is just one more eerie aspect of the society for Montag to rebel against.
In Fahrenheit 451, there are a number of events and characters which contribute to Montag's change. Here are some examples:
- Clarisse McClellan: Montag's sixteen-year-old neighbor is unlike anybody else Montag has ever met. In their first meeting, her question to Montag ("Are you happy?") prompts him to start questioning his chosen profession and his values.
- Mildred's attempted overdose: When Montag's wife tries to kill herself, Montag is horrified by the attitude of the two men who treat her. He is particularly shocked by the fact that Mildred appears unable to recall what happened when she wakes up the next morning and flatly denies that she would do something as "silly" as take all of her pills. This event leads Montag to realize that people in his society are both empty and disconnected.
- Clarisse's death: When Montag hears that Clarisse has died, his reaction is both physical and emotional. The next morning, for example, he wakes up with "chills and fever," the first time that he has been sick in a very long time. He does not go to work that day and asks Mildred how she would feel if he quit his job. Clarisse's death therefore makes Montag realize that he can no longer ignore his rebellious feelings.