Mom and Allen arrive at Dad's house the next morning. Susannah races to their car and explains that Dad kidnapped her. She tells the reader that Dad had already told Mom what happened the night before: after Susannah banished him, he'd gone upstairs to monitor her through a room with thin walls. He'd nodded off but had woken up when he heard her trying to break out, and had found Susannah barricaded in the bathroom. After taking an hour to talk her out of the bathroom, he'd sat with her until dawn. He and Mom spoke on the phone and agreed that Susannah needs to be admitted to the hospital, but that she shouldn't be placed in a psychiatric ward.
When Cahalan offers up Dad's version of events, she reminds the reader that she's an unreliable narrator. Mom and Dad's decision to admit Susannah to a hospital shows their love for her, though Susannah's behavior suggests that loving her won't be an easy task right now, particularly since she believes Dad is a murderer. His night with her, however, shows that he desperately loves Susannah and will care for her at all costs, even when it's heartbreaking for him.
Back in Dr. Bailey's office, Dr. Bailey insists that Susannah is suffering the classic symptoms of alcohol withdrawal: anxiety, fatigue, irritability, nightmares, seizures, and hallucinations. He insists that she just needs to stop partying and take her medications. Mom lists Susannah's symptoms (seizures, insomnia, and paranoia, all of which is getting worse), and points out that Susannah hasn't had alcohol in a week. She demands that Dr. Bailey refer Susannah to the hospital. Dr. Bailey grumpily leaves and returns with news that NYU has a bed open on a 24-hour EEG monitoring floor.
Again, Mom and Allen's success in forcing Dr. Bailey to refer Susannah to the hospital shows that it is possible to circumvent the medical establishment, and therefore sets an example for other families in similar situations. Comparing Dr. Bailey's diagnosis with Mom's list of symptoms makes it clear too that families' testimony needs to be taken seriously. Mom has spent time dealing with this new Susannah, while Dr. Bailey hardly knows her—and doesn't seem to care to know more.
An hour later, Mom, Allen, and Susannah enter the lobby of the NYU hospital. As they locate the admittance desk, Susannah demands coffee. Mom looks annoyed but allows Susannah to leave to get coffee. When Susannah returns, Mom asks her why she's smiling funny, and then Susannah has another seizure.
Mom still desperately wants to believe that this version of Susannah is the Susannah she knows and loves. By offering her this moment of independence, Mom shows Susannah she cares about her.
Susannah tells the reader that after this point, she remembers little more than hallucinations from her time in the hospital, and she believes that her "self" was truly gone. This begins her "lost month of madness."
In setting up this split identity, Cahalan insists that the reader consider the Susannah in the next chapters to be an entirely different person. This in turn sets her up to integrate the two identities in Part 3.