Final answer:
The man walking toward the heroine as the music grows louder and more discordant may be implicated just before the sound of a breaking guitar string is heard, intensifying the sense of danger in the film scene.
Step-by-step explanation:
The question appears to be related to a scene set in a movie, possibly involving the breaking of a guitar string as a dramatic device to introduce or signify impending danger to the heroine. The sound of a breaking string is closely tied to the suspense of the scene. If we interpret the question in the context of the provided information, it seems that the person who walks by, playing the guitar just before the sound of a breaking string is heard, could be inferred to be a man walking toward the heroine as the music gets louder and more discordant, heightening the sense of threat. However, without a specific reference to a breaking string in the texts provided, there is no clear answer to the question. It should be noted that guitar strings produce sound by causing air molecules to oscillate, creating sound waves as described in Figure 15.2, and while the sound of a string breaking is distinctive, the provided texts do not directly mention such an event occurring.