Deus Ex 'Scuse Me

Any quick, cheap device that serves to remove a character from a scene so a plot point can take place.

Example: A kid wanders into an antiques store, and the owner tells him not to touch anything. Suddenly, the phone rings. When the owner leaves to answer it, the kid touches something and it breaks. Cue plot. The in this scene is the off-screen phone call—it draws the owner out of the scene so the kid can break the antique.

The inciting incident in a often requires immediate attention, so the character has to rush out quickly. Phone calls are used frequently nowadays. Other urgent excuses include oven timers, guests arriving, someone calling for the character, forgetting an item and having to go back for it... the options are as endless as the writer's imagination.

Sub-Trope of Room Shuffle. Compare I Need to Go Iron My Dog when it's the character making an excuse to call themselves away from a room. This trope may be induced by others when We Need a Distraction. Name derived from "Deus Ex Machina"—instead of something randomly showing up to save the day, it's something randomly showing up to cull the cast.

Film

 * the 1998 film version of The Avengers. Steed and Mrs. Peel are at Wonderland Weather getting a tour from the receptionist. There's a noise (telephone ring?) elsewhere and the receptionist leaves, allowing Steed and Mrs. Peel to look around unnoticed.
 * Speed (1994). Howard Payne happens to be using the bathroom precisely when
 * Bastian always has something happen that lets him swipe The Neverending Story from the librarian's grasp.

Live-Action TV

 * Used twice in the TV adaptation of Goosebumps' "The Haunted Mask", both with a ringing phone—the first time, the mask shop owner is called away, allowing Carly-Beth to explore the forbidden section of the mask shop where she finds the haunted mask. Second time, Carly-Beth's mother wants to check on her costume (she thinks Carly-Beth is going out as a duck), but a phone call draws her into another room, allowing Carly-Beth to slip out.
 * Wonderfalls uses this from time to time. Once, Eric faints at a wedding chapel and the receptionist goes to help him, allowing Jaye time to steal info from their records. Another episode, Jaye's mother leaves suddenly because she "has to pee like a racehorse;" once she's gone, Jaye can speak privately with her therapist.
 * Law and Order does this a lot- pick a series, pick an episode, someone answers their cell and walks out of the scene.

Theatre

 * In One Touch of Venus, Savory is called away by Molly to settle something with Customs House about that ancient statue of Venus he has just acquired, leaving it alone with Rodney. When Savory returns, the statue is gone. So is Rodney, the only person who saw Venus come to life.