Periscope Clip from "Hell Week" episode of MacGyver

A persicope plays an important role in the "Hell Week" episode of Macgyver. A physics student David offers to show his friend Janet his top-secret barricade and takes her to his dorm room. They go in, unaware that fellow classmate and competitor Geoffrey has observed them. He goes into his room across the hall and uses a parabolic microphone to listen in. David explains his barricade: a garage door opener mechanism that barricades the door. His secret is a miniature model of the room, including the barricade which closes and opens. The peephole has a periscope which leads to the model. When the miniature barricade is closed, the real barricade is open and vice versa. When someone uses a scanner to open the barricade, they're actually closing the barricade.