Yes?
Do you want to know or have you figured on a certain someone? The authority I speak of is my niece who is full-grown and a fanatic about GoT, and follows a certain site to which someone associated with the show apparently posts (in cognito of course). I tend to believe it, because I don't mind spoilers that much, and my niece laid out
every bit of last season before we even saw it and it ALL came to fruition exactly as she told me she had read. So, I'm jazzed.
I haven't heard anything about Tyrion's fate, but I want to believe that he'll make it to nearly the end of the last season, if not all the way. I know it doesn't necessarily mean anything as we're dealing with character slayer George R.R. Martin, but Tyrion is one of the most put-upon characters in the whole run of the show (except for maybe Sansa and Arya, oh yeah, and Theon) and I'd love it for him to make it till the end and doing something massively heroic. Just in my opinion, I think he's been the one character who has been our voice for the show and I'd love him to win out.
P.S., that shot of the guy above with the flaming sword is massively cool! You can see it again very quickly in Trailer #2 when Jon is standing on the cliff/hill and there are two men flanking him, fighting. Mr. Flaming Sword (is his name Bendric Dardarion or something like that?) is to his right and you can catch the fire blade really quickly. So very cool.