Dying for a cause—particularly the cause of books and knowledge, and more generally, to live a life congruent with your values—plays an important role in the novel.
If Clarisse gives Montag his first glimmer of a different approach to life, the woman who dies rather than give up her books when the firemen arrive gets Montag's mind churning even more profoundly. His curiosity about these objects that he has thoughtlessly and joyfully incinerated for so many years is piqued when he realizes that some people would rather die than live without them.
As Montag's view of the world becomes increasingly focalized and crystallized, the idea of himself dying for a cause comes more and more clearly into view. He partners with Faber, a former professor who is willing to take risks if he believes there might be something worthwhile in it—even if only Montag's sincerity in pursuit of undermining a society that bans the real pursuit of knowledge. In the end, Montag is willing to risk his life for the cause of building a book- and knowledge-based world.