Guest Stars Jesse Williams as Dr. Jackson Avery Sarah Drew as Dr. April Kepner Jason George as Dr. Ben Warren Nora Zehetner as Dr. Reed Adamson Alan Mandell as Henry Stamm Amy Farrington as Mary May Demi Lovato as Hayley May Emily Bergl as Trisha Austin Highsmith Garces as Amber Courier Marion Ross as Betty Donahue Jonathan Goldstein as Ken May Co Starring Mark Saul as Dr. Steve Mostow Gloria Garayua as Dr. Graciella Guzman Denice J. Sealy as Nurse Regi Davis as Dr. Kevin Fisher