Use two dashes for interruption:
TERRY
Listen to me, Margot--
MARGOT
No, you listen!
Use three dots for pauses in dialogue. This is an imperfect system, but an improvement over the bland PAUSE or BEAT in screen direction.
WALLY
Dad, I’ve kept something from you for a long time. And...I just can’t any more. I...I have to tell you... I’m a Green Bay Packers fan!
DOUBLE-DASHES:
Another stylistic choice for screen direction is the double-dash. You’ll often see this, for instance, from Reindeer Games:
The ugly staffer curls his lip. Nick smiles. Rudy moves on, taking his tray off the rail and turning--right into the chest of The Alamo. He looks up--into the most scarred and vengeful face a man could ever dread to see. The Alamo’s a lifer. Many times over.
Dashes can also be within the body of the screen direction paragraph, stylistically adding space, to give the feeling of movement, of speed. For instance, from Constantine:
John quickly wraps the cloth tight around his hand. Angela spins, eyes seeing only darkness as the sounds get CLOSER -- ghastly sound of MOVEMENT in the fringes of light.
The cross now resembles a dying wire filament and with every second the circle of light gets smaller and those SOUNDS GET CLOSER. John takes out his special lighter.
JOHN
Close your eyes.
They are now standing in pitch darkness.
ANGELA
Why?
JOHN
Suit yourself.
John flicks the lighter and in one powerful motion --sweeps his arm up as he lights his hand. Sacred cloth catches fire -- then IGNITES with a brilliant retina-searing FLASH -- blinding Angela and illuminating a ---- CIRCLE OF WINGED DEMONS -- a roiling broth of reptilian death -- right there -- ready to pounce.
