I watched the teaser and I can confidently say that there is no trace of Sean in it. Ned did not survive and will not survive. People need to just get over it. His head is rotting on a pike on the walls of King's Landing. Everyone who saw the last episode saw it. To those who haven't read the books yet insist on voicing their opinions they need to shut up and go and read them otherwise they are simply showing their ignorance to the whole world. Without Ned's death there is no catalyst for everything to come in the remaining books. Benioff and Weis are not so stupid as to go THAT far off of the story so as to chance enraging the volumes of die-hard fans of the books, who all know that Ned is DEAD. Belfast is one of the few places Sean has NOT been to so far this year and the closest his current projects will be taking him is up to Yorkshire/Lincolnshire for Magnificent 11 filming. If he did film some flashback scenes he must have made a stealth trip over there for a day and managed to avoid everyone who blogs and tweets about the production.