Dr. Najjar tells Mom and Dad that he'd like to start Susannah on steroids, and mentions a doctor at the University of Pennsylvania who specializes in autoimmune diseases. He then says he'd like to consider a brain biopsy. Dad bristles, but Dr. Najjar says he'd choose to do it even on his own child.
It's important to remember that all of these procedures require permission, even if they're necessary. Thus, Dr. Najjar must gain Mom and Dad's trust to convince them that this is for the best.
Later that afternoon, Dr. Russo arrives and confirms that the team would like to perform a brain biopsy. Mom pulls Dr. Russo into the hallway with questions, but starts sobbing instead. In his journal later, Dad would write about his mother, an RN, who spoke often about bad things happening during brain surgery. After Dr. Russo's visit, Dad walks to a church and prays. Mom, an agnostic Jew, prays with a Baptist coworker later that afternoon. Susannah remains unaware and gleefully tells friends that she's getting a brain biopsy. When one friend expresses concern, Susannah hangs up and bursts into tears.
Mom and Dad's fear about the brain biopsy comes from the fact that because doctors know so little about the brain in the grand scheme of things, cutting into it can be extremely risky—it's relatively easy for things to go wrong without warning. This also situates the memoir as a product of its time, as medicine will presumably one day be able to diagnose diseases without needing to perform these invasive procedures to gather information.
Over Easter weekend, a nurse describes to Mom and Dad how they'll perform the surgery. Susannah is silent through the nurse's description, but begins crying later. Dad is there when she cries, and he cries too. Suddenly, Susannah starts laughing and tells Dad he looks funny when he cries. He reminds her of their motto that the slope of the line is positive and brings her an Easter basket the next morning.
Though the childish Easter basket is charming at this point, these symbols of childhood will later become something that Susannah chafes against.
On Monday morning, an orderly fetches Susannah for surgery. A resident shaves a portion of Susannah's head, and Dad reminds her again of their motto. After the nurses put Susannah under anesthesia, the surgeon takes four hours to drill through Susannah's skull, take a cubic centimeter of brain tissue, and then replace the portion of skull.
Again, by describing her procedure in such detail, Cahalan seeks to shed light on these procedures that many people are afraid of. This allows her to continue her project of educating people about her disease and the ways doctors deal with it.
Susannah recounts another memory or hallucination of being led through counting down from 100 in preparation for surgery, and then waking up in a recovery room. She can't move, but tries to wave at Mom, Dad, Stephen, and Allen. A nurse gives Susannah some water when she asks, but then tells her that she can't have anymore. Susannah informs the nurse that she'll tell everyone how the nurse treated her when she gets out of the hospital. Susannah loses consciousness and then wakes up, alone, in a single person room. She desperately needs to urinate and pushes until her catheter comes undone. Urine sprays everywhere, and she calls for a nurse. As two nurses clean her, Susannah discovers she can't move her legs.
Even though the surgery and biopsy are very much good things in the long run, Cahalan doesn't shy away from describing the uncomfortable, lonely, and scary recovery process. This continues to show that even "good" medicine often isn't easy. Further, the fact that Susannah cannot move her legs makes it clear that mistakes are still made—though, again, this mystery is never solved and she does regain use of her legs.
Hours later, at 11 pm, a nurse tells Dad that Susannah is in the ICU. He lets himself into her room, and uncharacteristically, Susannah recognizes him. They hug, and then Susannah tells him that she can't feel her legs. Dad calls a resident, who rushes Susannah away for an emergency MRI. When the MRI comes back normal, Dad finally goes home.
When Susannah recognizes Dad, it suggests that she's beginning to recover and regain some ability to more effectively communicate. Her recovery isn’t straightforward, however, as the scary MRI experience shows.