Of course, no Asgardian prison could hold the God of Mischief, as we can see in the latest 'Thor: The Dark World' poster. Loki (Tom Hiddleston) will return to help out (I think) his step-brother Thor when the movie opens on November 8!
The wise and mighty All-Father looks imposing as hell in this new poster, featuring Sir Anthony Hopkins as Odin. Sounds like the ruler of Asgard will see plenty of action in Thor's next screen adventure. According to Marvel, Odin will "...help guide his son though his toughest challenge yet...". I guess those Dark Elves really are as malevolent as they look.