A planned romantic rendezvous for Meredith (Ellen Pompeo) and Derek (Patrick Dempsey) is interrupted by a train wreck which brings dozens of victims into Seattle Grace. Among these are a twentyish woman named Bonnie (Monica Keena) and a middle-aged man named Tom (Bruce A. Young), who form an unusual bond while impaled together on a pole. Meanwhile, a critical operation is put on hold while Cristina (Sandra Oh) searches for the patient's missing leg; Addison (Kate Walsh) and Izzie (Katherine Heigl) struggle to save the life of a burn victim's unborn child; and Alex (Justin Chambers) tries to care for his patient Mary (Juliette Jeffers), despite the obnoxious interpolations of Mary's friend Yvonne (Kym Whitley)--whose ceaseless carping about Alex's medical skills and bedside manner cause him to wonder if he has chosen the right profession after all. ~ Hal Erickson, Rovi