How does the author use foreshadowing in Shattered Mirror?

There's an important moment of foreshadowing in the first chapter when Sarah has just killed the first vampire. Sarah stares at the creature for a moment, "wondering how any person would willingly become a creature who fed on humanity." Sarah will become a vampire at the end of this book and she hungrily takes in the blood that's offered to save her life. Even then, it's noted that any true daughter of the Vida clan would kill herself rather than live as a vampire but Sarah's will to live is stronger than that.