Big Year interview - Dr David King

Trauma surgeon Dr David King ran the Boston Marathon in three hours and 13 minutes this year. Not long after he'd finished the race, the first of two pressure cooker bombs exploded, the second bomb detonating 13 seconds after the first, near the marathon's finish line - while thousands of people were still running. Three people were killed, more than 260 injured, and David King went straight to Massachusetts General Hospital to operate on the casualties.