A group of young men and women, all dressed in black, marches down a busy street in the heart of Times Square. Walking in formation, they dodge parked cars, bicycles and pedestrians, as the man leading them belts out a song.

“Sunset Boulevard, ruthless boulevard / Destination for the stony-hearted.”

This ambitious scene from the director Jamie Lloyd’s Broadway revival of “Sunset Boulevard” hinges on a live tracking sequence that goes backstage and spills onto West 44th Street. It’s shown in real time on a massive LCD screen to the audience inside the St. James Theater, but passers-by — both unsuspecting and calculating — get a front-row view, at least during the number’s three-minute outdoor portion.

“We’re sort of crossing our fingers a bit every night,” said Nathan Amzi, who designed the scene with Joe Ransom and Lloyd. Everyone, he added, “has to have laser focus to make it work.”

Through rain, bone-chilling temperatures and the crush of crowds from neighboring shows, this scene, which takes 62 people to pull off, goes on.

The title song, “Sunset Boulevard,” which is sung by the hapless young screenwriter Joe Gillis (played by Tom Francis), functions as a sort of dream sequence in the musical. The character contemplates the circumstances that led him to take up residence at a Los Angeles mansion as the boy toy of the faded silent film star Norma Desmond — and tries to justify them.