- "The time varies from person to person, but we know that muscle impulse resumes after death... any death. They all come back. We all come back. This is a captive bolt pistol. It's used for livestock. Traumatic brain injury is the only thing that stops it. It's the only way to stop them. She'll turn, Liza. And we don't want her to turn."
- —Dr. Exner to Liza Ortiz[src]
Los Angeles, California
Dr. Bethany Exner is a doctor working for the United States Government.
When Elizabeth Ortiz visits the Ramirez home to check on Hector Ramirez, she finds the bed empty. Moments later, Dr. Exner enters the house with Cynthia Ramirez, who is grateful for Dr. Exner transferring Hector to a medical facility for proper care. Dr. Exner introduces herself to Liza and begins to question Liza's medical history, fully aware that she is not an actual nurse, but pleased that she has been helping neighbors in the safe zone. Dr. Exner enlists Liza to assist her in caring for other patients in the safe zone, and examines Nicholas Clark, who is supposedly recovering from a drug addiction.
Later that night, Dr. Exner and several members of the National Guard remove Griselda Salazar from the Clark home to be transferred to the medical facility. Much to Liza's surprise, Nicolas is also removed from the home and she pleads Dr. Exner to allow Nicholas to stay behind. However, Dr. Exner persuades Liza to join her to the medical facility, as she knows Liza will be a useful asset. Ultimately, Liza decides to leave with Dr. Exner, along with Griselda and Nicholas.
Bethany is seen at a medical ward in the command post tending the wounded along with Liza, Nurse Hodges, and several other medics. She tells Liza that she is grateful for her services as they had been short on medical staff after her best nurses were taken away for a mission. After a new soldier comes in, Bethany examines his wounds and sees bite marks on him. She immediately authorizes the euthanization on him, and after Liza asks her why, she responds that he will turn and will begin "tasting the neighbors".
After Liza stumbles upon the holding pens in an attempt to find Griselda, Bethany finds her in another ward. She tells her that Griselda is in septic shock from the amputation. After Griselda starts muttering about the war in Spanish, she dies from the lack of blood to her brain. Bethany takes out a captive bolt pistol and explains to Liza that after any death, the host will turn into an infected, and the only way to stop them from turning is blunt trauma on the head. She is about to shoot the deceased Griselda to prevent her from turning, but Liza does it instead.
Dr. Exner continues to care for the twenty patients remaining in the medical ward, along with a dozen of her nurses and medical staff. She radios Edwards Air Base to arrange for evacuation of her patients and staff. She is pleased to inform her fellow survivors that the military has agreed to send an evacuation helicopter. However, once she sees zombies overrunning the facility, she radios the air base to check on the status of her helicopter. The military states that they are assessing the situation, but she sees the helicopter fly away, realizing that they have been abandoned. She tells her nurses and able-bodied patients to flee for the trucks outside before they leave. She remains behind with the patients who are unable to move. When Liza and her group arrive at the ward, they find that Dr. Exner had mercifully executed the remaining patients, to avoid them from being eaten alive by the zombies. Liza attempts to persuade Dr. Exner to flee with then, but she refuses. Instead, she remains motionless as she stares at the bolt gun in her lap, indicating a possible suicide attempt.
- In an interview, Showrunner Dave Erickson commented the following regarding Dr. Exner's fate:
"In my mind, she was planning to use that cattle pistol on herself. Her mission has failed and she had a look into what our characters don't understand yet: this is the end. She is left in a place where I don't think she sees any way to bounce back from it. We have no plans for Exner right now."