Six top writer-producers -- Vince Gilligan ("Breaking Bad"), Howard Gordon ("Homeland"), Shonda Rhimes ("Grey’s Anatomy," "Private Practice," "Scandal"), Glen Mazzara ("The Walking Dead"), Veena Sud ("The Killing") and Terence Winter ("Boardwalk Empire") -- talk writers' block cures, the "torture" of Twitter and the most painless way to kill off your lead.