The clip that I chose is a scene from the movie Harry Potter and the Chamber of Secrets. Right before the scene Harry was dueling his rival, Draco, who then cast a snake from his wand. Suddenly, without his knowledge, Harry starts to speak to the snake in some sort of foreign language.
Right before Harry begins to talk to the snake, all the ambient sounds coming from all the other students who were just watching Harry and Draco duel fade out, only leaving Harry's voice and the music. The volume of Harry's voice was also increased slightly, giving his voice a large amount of presence, giving off the effect that possibly this is something happening inside his head, subconsciously, is an internal force, etc.
Then, to increase the emphasis on that same effect, as soon as Professor Snape steps in to dispose of the snake, the music cuts out and the volume of the ambient noise is restored.
Another major part of this scene's sound is the music behind the visuals, and how it transitions to match and emphasize each mood in the scene. As Harry and Draco are dueling the score is very loud and exciting, matching the excitement of two rivals battling each other. Then, after some silence as Harry begins to talk to the snake, an ominous and erie music starts to play softly in the background. This helps darken the mood for the audience and suggest that what is happening on screen isn't good and something bad might happen to the main character. Also, cutting the music at the same time the ambient sound returns helps with the effect that Harry's ability to talk to snakes is an internal force, subconscious act, etc.