The editing in Michael Soavi's Stagefright (1987) effectively disorients the audience, thus unnerving them and making them more susceptible to shocks and fear.
A mad slasher (wearing an owl mask) is stalking six people trapped in a theater. Alicia (Barbara Cupisti) runs into the shower room, where she finds Laurel (Mary Sellers) lying in the left stall, bloodied but still alive. Alicia hears the slasher approaching from the hallway.
Cut to the slasher in the hallway.
Cut to Alicia, having heard the slasher, closing back the curtain on Laurel in the left stall, then hiding in right stall.
Cut to Alicia in the right stall, pulling the curtain closed.
Cut to the slasher entering the shower room. Two curtained stalls before him. Laurel on left (behind the bloodied curtain). Alicia on the right.
Cut to Alicia in the stall.
Cut to the slasher's POV (point of view), coming toward the two shower stalls.
Cut to the slasher's silhouette across the curtain. He is drawing near.
Cut to Alicia's worried expression. Her eye line is directed at the curtain. Her acting and the eye line match implies that the silhouette is her POV. That the slasher is approaching her stall.
Cut to Alicia backing against the wall. Her staging reinforces the notion that the silhouette is against her curtain.
Cut to slasher drawing nearer to the curtain. Close enough that his owl mask is visible. Then in the same shot, he yanks aside the curtain.
Cut to a close up on Alicia. Her eye line is directed toward the slasher in the previous shot. She appears to be looking at him.
Cut to the slasher drawing nearer. The mask's eye line directed at Alicia in the previous shot.
Cut to Alicia's POV of the slasher looming over Laurel. In the same shot, he raises Laurel, who looks toward Alicia in the right stall.
Cut to Alicia looking back at Laural, eye line match to Laurel.
Thus Stagefright's editing has fooled us. The POV shots, eye line matches, acting, staging, and editing suggested that the slasher was approaching Alicia's stall. But it was Laurel's. He still doesn't know that Alicia is there. She is still safe.
For more examples of how editing can disorient an audience, see my posts on Vacancy and Galaxy of Terror.
For more information on editing in horror films, see Horror Film Aesthetics: Creating the Visual Language of Fear. This blog represents a continuing discussion of my views on horror, picking up from where the book left off.