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At the very final scene of the second season of Game of Thrones, something weird happens.
Sam notices a White Walker along with an army of wights, all heading his way. Since he can't run, he hides. But when we see the White Walker, it seems that he and Sam look at each other.
And for some reason, the White Walker doesn't kill Sam. And even if he didn't really see him. It was my impression that they could sense humans in their vicinity. Surely Sam would have set these internal alarms of the icy CGI warrior.
So how is Sam alive at all??