GREY'S ANATOMY - "An Honest Mistake" - Derek's confidence is shaken like never before as he faces off with Addison over what course is best for their dying pregnant patient; Cristina calls the abilities of a renown surgeon into question after she botches a standard procedure; and Bailey, who has decided to pursue a fellowship in Pediatrics, is appalled by the Chief's less-than-stellar recommendation letter, on "Grey's Anatomy," THURSDAY, FEBRUARY 19 (9:00-10:02 p.m., ET) on the ABC Television Network. (ABC/RON TOM) SANDRA OH, KEVIN MCKIDD, FAYE DUNAWAY, SARA RAMIREZ