HARRISONBURG, Va. — When a person you know well makes a regrettable choice, how do you reconcile what you know about that person with his or her actions? And how do you share what you know about this person without seeming to excuse the action? These questions confronted Luke Hartman, vice president of enrollment at Eastern Mennonite University, when he saw on national news the video of resource officer Ben Fields flipping over a black student’s desk and tossing her across the classroom in a South Carolina high school.