Monumental tech snafu

The Marion Davies movie THE FLORA DORA GIRL is set around the turn of the 19th/20th century. She and the other are at the beach in ancient 'bathing suits'. The reel changes and you see the camera crew and people on the set getting ready to shoot the scene! First the camera is blocked by some guy's shoulders, then he gets out of the way and you see an AD in vintage 1930 Hollywood attire barking out directions, then the guy with the clapboard and people getting in place appear and then the film continues! All of this is on screen for maybe 10 - 15 seconds. Astounding! How does something like that happen? I have it on tape from TNT.