After Scrappy is left alone and tells the audience he's going to try and catch the villain with one of his 'Scrappy Traps', the scene cross fades momentarily to the later shot of the rest of the gang on the rooftop looking out for The Blue Scarab before abruptly cutting to the scene of the gang running towards the elevators. It is possible that this scene which leads to a gag with Scooby caught in the elevator with The Blue Scarab was added at a later point in production to fill time and was clumsily edited in.