Students Shara Evans, of West Bloomfield, Mich., left, and Maia Frieser, of New York, act during a "zombie apocalypse" exercise, which included students dressing up as the undead, in Ann Arbor, Mich. Tuesday April 23, 2013. The exercise was designed to get School of Public Health students thinking about what the appropriate response should be during a disaster. (AP Photo/Paul Sancya)