What should a therapist do when a patient reveals critical information at the end of a session? It’s a near-universal experience among mental health practitioners: a patient drops a bombshell—a critical disclosure that moves the treatment forward—on their way out, with a hand on the doorknob. This “doorknob moment” creates a stressful dilemma for clinicians, especially when the patient is distraught. Should the clinician end the session on time, or run over and be late for the next patient? Here, seasoned psychiatrist Daniela V. Gitlin provides clinicians with a clear, evidence-based answer. By conceptualizing the functional differences between patient and therapist in the treatment relationship as a metaphor for the functional differences between right and left cerebral hemispheres, Gitlin’s argument yields a comprehensive explanation for why doorknob moments occur, why they are necessary to prevent treatment stagnation, and why ending on time makes patients feel safer to deliver them.