This scene is pretty much just the tourists watching Wonka as he sings, screams, and shouts like a madman. Honestly, it seems like this scene was specifically to show the viewer that Wonka was absolutely losing his mind. Why else would the image of a headless chicken show up?
Cats
There is, quite literally, not one thing about this movie that makes sense. The cats, played by insanely famous actors and celebrities, don't really know what's going on either, apparently. Instead of picking out just one scene from this movie, it's safe to say that every part of this movie makes no sense.