Solution to Back on the Move

During hunt, the Twitter stream linked from the puzzle was updated in real-time by 4 people independently wandering around MIT, each taking pictures about once or twice a minute. Hunters use the pictures to find the people in real life, and get some info worn on each person's hat ("1: N", "2: E", "3: N", "4; A"). Combining the letters in the order specified gives the answer NENA.