In the spirit of Valentine's Day, Meredith and Derek try to have a night to themselves when Lexie offers to watch Zola; Callie hands babysitting duties over to Mark so that she can surprise Arizona with a romantic evening; and Ben proves to Bailey that he knows her better than she thinks. Meanwhile, the ER fills with romantics, including a 10-year-old girl who has an allergic reaction to chocolates from her valentine and a man who is hit by a car while chasing down his frustrated girlfriend.
Elenco: Ellen Pompeo , James Pickens Jr. , Chandra Wilson , Justin Chambers , Kevin McKidd , Jesse Williams , Patrick Dempsey , Sara Ramirez , Sandra Oh , Jessica Capshaw , Sarah Drew , Camilla Luddington , Caterina Scorsone , Giacomo Gianniotti , Kelly McCreary , Katherine Heigl , Chyler Leigh , Eric Dane , Kim Raver , T.R. Knight , Jerrika Hinton , Jason George , Isaiah Washington , Kate Walsh , Martin Henderson , Brooke Smith , Jake Borelli , Greg Germann , Chris Carmack , Tessa Ferrer , Gaius Charles , Anthony Hill , Richard Flood .