GREY'S ANATOMY - "This Is Why We Fight" - As word of Seattle Grace's financial trouble spreads, Catherine encourages Jackson to move to Boston, and the interns fear they might lose their jobs. Meanwhile, the doctors meet with a potential investor in a last-ditch effort to save the hospital, and Alex impresses Jo while caring for a patient, on "Grey's Anatomy," THURSDAY, FEBRUARY 21 (9:00-10:02 p.m., ET) on the ABC Television Network. (ABC/RON TOM) CAMILLA LUDDINGTON, JUSTIN CHAMBERS, WILLIAM JENNINGS