In Ray Bradbury's Fahrenheit 451, there are several things I connect with. The first is Mildred's betrayal of Montag. This is a clear indication of just how far apart this married couple has become. It is as if they really don't know each other anymore, and Mildred—a stranger more than a wife—has betrayed Montag to Beatty and the others.
Another thing extremely obvious to me is the reversal of positions: of Montag, the fireman who burns houses with books, and Montag, the lawbreaker whose house is burned because of books. In this case, the burning of the home previously where the old woman not only refused to abandon her books, but lit the match herself, feels like foreshadowing of this moment in Montag's life. He was appalled when he witnessed the old woman's death because of her commitment to books, and now it has become his reality: he is experiencing first- hand what he has been responsible for doing to others, throughout all the time he has been a fireman—it has now becomes his turn, as with the old woman, to decide how important having books is to him.
It is in this section that Montag chooses to change his life forever. First, he kills Beatty, showing how far he is willing to go; next he plants books in Black's house and reports his fellow-firefighter for having them; he runs from the Mechanical Hound—"beating" it; and, makes it across the river to join others like him who have chosen to leave society to read, share, memorize, and enjoy the knowledge of books—to build a new place to live.
Granger, one of the men Guy Montag meets on the other side, likens the destruction of their society, as well as their plan to rebuild, to the mythical phoenix:
There was a silly damned bird called a phoenix back before Christ, every few hundred years he built a pyre and burnt himself up...But every time he burnt himself up he sprang out of the ashes, he got himself born all over again. And it looks like we're doing the same thing...
The third section of the book, in an odd way, is like Montag's religious conversion (theme: change and transformation). Montag had heard "the Word" before, from people like Clarissa and Faber, but had been slow to move or change. The conversion is a dark one, with the ghastly murder of Beatty, but symbolically this represents rejection of an old way of life to make way for the new. In this story of growing self-awareness and rebellion, Montag becomes a "founding-father" of a new society.