A station announcement may be audible while the central characters barely acknowledge it. The voice can make their private conversation feel part of a larger public place.
Listen for usable information
Does the announcement specify a destination, a delay or an instruction? Write down only what is intelligible. If the words are indistinct, describe the voice’s presence rather than guessing a message from the location.
Watch whether anyone responds
A character might check a clock, change direction or continue talking. That response can connect the background voice to the action. An announcement without an obvious response may still establish routine or interrupt a sentence, but its effect needs a particular observation.
Replay the scene at a comfortable volume and compare your attention before and after noticing the voice. Do not assume the sound was captured on location or identify its performer without evidence. Your viewing note can stay focused on the finished scene: a public message continues while two people try to complete a private exchange.