Mitt Romney's speech to supporters in Des Moines Friday was cut short by a fire drill thanks to a bag of burning microwave popcorn. The former Massachusetts governor and soon-to-be official 2012 presidential candidate was fielding questions about his commitment to the first-in-the-nation state at Des Moines' State Historical Society of Iowa building when a fire drill forced him to cut his appearance short. "Discretion is the better part of valor," Romney said, urging people to head outside as the alarm sounded in the background. "I wasn't trying to get out of tough questions, I promise," he said later.