Before coming to the Wilds, Lena never would have believed that the communities were really the ones who were sick. She had grown up hearing that the communities were clean, tidy and perfect, and that the Wilds were sick, dangerous and evil. But, once she escaped to the Wilds, she learned that she grew up believing a lie.
In Pandemonium, by Lauren Oliver, the author uses the setting and dialogue to take the tone of safety and happiness that is associated with the communities and the tone of danger and sickness that is associated with the Wilds and shift them so the readers view each place in a new light when the reach the conclusion of the book.
To switch the tones from the communities and the Wilds, the author uses the dialogue of the characters