What is the purpose of the final moments of the play after it’s announced that the true inspector is in the town when all dialogue stops and the actors create a slow motion pantomime and tableaux?

Finally, Robey suggests that the mute scene also emphasizes the role of the audience. As they stare at the tableau (if it is done properly, of course), the audience members will begin to feel “uncomfortable and self-conscious” and “are reminded that they are looking at a parodic image of themselves onstage, both by the play’s epigraph (‘Don’t blame the mirror if the mug is crooked’) and by the mayor’s line shortly before the denouement, ‘Why are you laughing? You’re laughing at yourselves!’” The audience should feel that this is a wakeup call—that a moral message is being imparted to them.