GREY'S ANATOMY - "Perfect Little Accident" - When famous surgeon Dr. Harper Avery is rushed to Seattle Grace-Mercy West, the staff is surprised to discover that one of their own is related to this legend, and his unorthodox request for his surgery causes tensions between Derek and Richard. Meanwhile Callie and Arizona try to help Teddy and Sloan move on from their pasts and find greener pastures, on "Grey's Anatomy," THURSDAY, MARCH 4 (9:00-10:01 p.m., ET) on the ABC Television Network. (ABC/ERIC MCCANDLESS) ROBERT BAKER, SANDRA OH, KEVIN MCKIDD