Doug Milano, an East Hampton Middle School math teacher who recently ran his first marathon, “dying” after having moved up to fifth place in the Newsday race by the 18-mile mark, had a much easier time of it in the Bonac on Board to Wellness 5K on May 23, crossing the Main Beach finish line ahead of 637 fellow participants, a number of them students or former students of his, in 17 minutes and 51 seconds.