As hospitals incorporate information technology (IT), their operations become increasingly vulnerable to technological breakdowns and attacks. Proper emergency management and business continuity planning require an approach to identify, mitigate, and work through IT downtime. Hospitals can prepare for these disasters by reviewing case studies. This case study details the disruption of computer operations at Mount Sinai Medical Center (MSMC), an urban academic teaching hospital. The events, and MSMC's response, are narrated and the impact on hospital operations is analyzed. MSMC's disaster management strategy prevented computer failure from compromising patient care, although walkouts and time-to-disposition in the emergency department (ED) notably increased. This incident highlights the importance of disaster preparedness and mitigation. It also demonstrates the value of using operational data to evaluate hospital responses to disasters. Quantifying normal hospital functions, just as with a patient's vital signs, may help quantitatively evaluate and improve disaster management and business continuity planning.