Chuck was a projectionist again two years later!

Columbo
"Double Exposure" (1973)
From Wikipedia:
Dr. Bart Keppel (Robert Culp) is a "motivation research specialist" who has written several successful books on marketing and made a name for himself on the subject of subliminal advertising (which involves inserting frames of an advertised product into the reels of a film; the frames at regular speed go by too fast for the conscious mind to note them; but subconsciously the viewer's mind picks them up and he will crave what is pictured). But Dr. Keppel's more lucrative sideline is blackmail: he takes pictures of his married clients with a girl hired to tempt them. When his latest victim, Vic Norris, balks and threatens to expose him, Dr. Keppel must kill him. Dr. Keppel uses a subliminal cut of a refreshing drink to lure Norris out of a screening room where he and a number of other executives are watching a promotional film that Dr. Keppel is supposedly narrating (in fact they are listening to a prerecorded narration), during which time Dr. Keppel sneaks out and shoots Norris in the building lobby, then arranges things to make it seem like the crime was committed by Norris's wife. When Keppel's projectionist Roger White (Chuck McCann) discovers the cuts and pieces together the plot, Keppel shoots him as well. This episode received the Emmy Award in the category for Outstanding Limited Series.


*** The trouble with reality is there is no background music. ***