1. There are evil in this world, not just in foreign countries. Those people can be intimidating and strong, can be well respected, can be a surprise, can even go un-noticed. As bad as they are, as unfair as it is, we often do not see them fall.
2. In the face of such evilness, some people think it is not worth to fight; some people do not have the courage to fight; some people never think about their own worthyness or courage or chance to win, they just fight, and they are heros. In the movie, Lily's father is a hero, he saved his daughter and saved Ming from the evilness, saved them spiritually with all he had.
3. Good, kind people can fail to keep the promise. In the movie, Ming failed to save Lily and failed Lily's father's expectation.
4. Despite all the guilt and regret, heartbreaking and hopelessness, Ming still chose to be resilient, chose to be a good, kind person, chose to pursue one's own happiness through honest competition and genuine help for others. He conquered many huge obstacles and fulfilled his childhood dream to be a doctor. Through his work he helped as many people as he can, bringing them from darkness to sight. That is meaningful and beautiful.
We cannot change the past, no one is perfect. But we can choose to be the best self, and always pursue sight in the darkest times. How Ming did it? It is in the movie.