BBH London ambushed a live audience of moviegoers in London with this stunt PSA on behalf of St. John's Ambulance  emphasizing the importance of knowing first aid. An idyllic family scene on the big screen suddenly turns ghastly when one of the daughters begins to choke on popcorn. Not knowing how to deal with the situation, the parents panic—and the mother cries for help as the girl goes limp. Suddenly, a woman stands up in the audience, shouts that she can help, and hurries backstage—she then appears on screen and saves the day. It's a clever trick that mostly redeems the unpleasant shock tactics. The audience applauds at the end, though it's unclear whether they really appreciated the experience or are just being polite to the actress as she returns to her seat. Via Osocio .