When Rosie makes her tap-dance exit out the door, the camera cuts to a shot of Shirley, Laverne, and Carmine. Then you hear a loud sound, which causes the studio audience to laugh suddenly. As Penny Marshall and Eddie Mekka try to maintain character and not laugh, Cindy Williams quietly asks Penny, "Did she fall?" which Penny confirms. Evidently, Rosie tripped on the stairs outside the door in view of the audience.