Don't forget the diegetic music—the music the characters themselves hear. Su-an’s unfinished song for her father, which she plans to sing at a school assembly, becomes the film’s thematic anchor.
Without spoiling too much for the uninitiated, the film pivots from survival horror to pure tragedy. The music shifts entirely. The percussion stops. The strings swell. train to busan music
The score even quotes this melody in the orchestral finale, tying the father’s redemption to the daughter’s voice. Don't forget the diegetic music—the music the characters