This is just as they are opening the gates to take Anna.
This is the final realization that this will be the last time he will ever see Anna. She will be taken in and saved, then she will live happily, without him.
She will live on with her prince, and probably forget her times with him as they grow old, he will become just another commoner to her as the years pass.
He will go back to living in the mountains, but he will never forget her. Her smile, her laugh, the lip biting quirk she has.
He will be left to his own devises. He will be left alone with Sven just like it was, but is that what he really wants? Are reindeer’s really better than people.
Are they better than the girl who made him feel something? Made him open up, finally show who he really was? Better than the girl who always worried for everyone but herself even when she was the one dying?
He finally realized here that the answer was no, she was better and that’s why he had to let her go.
He realized he needed her but she didn’t need him. But it didn’t matter because all that did was that she would be safe and be able to live her life.
This is his love being taken away from him, because as soon as the gates start to open he gives this face, this face that shows how scared he is to picture his life without Anna after she had snuck her way into it
That’s okay I didn’t need my heart anyway.