The Big Flush (High-Definition)

In a public restroom, the camera pans the closed doors of 4 stalls; the first has an "out of order" sign on it. We hear a gaseous noise, and one by one, three musicians (a guitar player, a bass player, and a trumpet player all wearing tuxedos) flush the toilets and come out of the stalls revealing their musical instruments. Finally, the last to be disclosed is an old lady, Pat (from the "out of order" stall). She goes to wash her hands and is shocked to find in the mirror that behind her, the three musicians, wondering where all the noise came from-- herself or the musicians.