On his deathbed, Xavier again mentions "the Sun Seeker" to subtly reinforce the idea that Seeking the Sun could be some kind of salvation. This pays off in the movie's climax when Caliban, intending to destroy himself rather than continue to betray his friends, throws himself into bright sunlight -- seeking sun -- but instead is unexpectedly transformed into the powerful being of light he was always meant to be (albeit after a painful transition).
The Phoenix-like "Sun Seeker" -- now in his true form -- then provides a way for the x-tots to cross the border over to "asylum" -- what appears to be some dimension- or time- or space-hacking exit to benign-looking, arm-waving aliens beckoning the kids to Deep Space Nine or Yoda's Hut or the Weinstein Company's daycare nursery. Thank god -- we're so tired of laser beams rising into space!
Right? Because we all recognized, halfway through the movie, that the "border" couldn't be a literal national border, and the "asylum" wasn't merely a political one... Because big pharma's ruthless mercenaries won't care about borders... Right? (Especially Canadian ones!)
Or should I have stayed for the end?