An Army Intelligence Officer, running in the 2013 Boston Marathon, was pulled out of the race prior to the bombing, and sent away to a hospital. The reason given - "dehydration" - seems very improbable for a young experienced athlete in top shape. Also, the normal treatment for dehydration is water, not hospitalization.
Did the Army personnel (or whoever pulled him out) know in advance of the explosion? A "controlled explosion exercise" of unprecedented scale was also happening PRIOR to the bombing. Coincidence?