The "Frozen" moment seems to be something added in to the later drafts because the original script did not have it. In the original screenplay Colter and Christina disappear through the train station tunnel. They're not outside. I think the kiss was off the train as well.
I doubt there would be a sequel and if there was one Duncan most likely wouldn't return to direct it.
I doubt there would be a sequel and if there was one Duncan most likely wouldn't return to direct it.