They must decide whether to flee the area and risk the "future" coming true elsewhere or stay and attempt to disrupt the broadcast to change their fate. 5 Ways to Generate More Ideas If you want to brainstorm your own, try these techniques:
The radio isn't playing music; it’s broadcasting a conversation from 20 years in the future that predicts the exact moment they will disappear. Discussion/Chat – ExtraMovies
While exploring a remote desert, three friends hear a whistle every night at exactly 2:17 AM. They eventually find an abandoned police car buried in the sand with a radio that is still playing. They must decide whether to flee the area