In Episode 4 'Cracking Up', Bob Mortimer showcases his newsreader skills, Judi Love introduces a furry friend, and a surprise celebrity guest invades Rob Beckett's personal space, sparking chaos. Additionally, one of the comedians experiences the serious giggles, and as the episode progresses, there is a tense effort to make Richard Ayoade laugh.

While the episode features all contestants, notable moments include Bob Mortimer's newsreader act and Judi Love's introduction of a furry friend. Rob Beckett is notably targeted by a surprise celebrity guest invading his personal space. The episode also highlights a contestant struggling with uncontrollable laughter, adding to the tension.

The surprise celebrity guest in Episode 4 invades Rob Beckett's personal space, which acts as a catalyst for comedic chaos and attempts to break the contestants' composure, particularly affecting Rob Beckett.

Episode 4 includes physical comedy elements such as Judi Love introducing a furry friend, which adds a tactile and visual comedic element. Bob Mortimer's newsreader skills also involve performance style humor. The episode uses these props and physical interactions to create tension and laughter among contestants.

While specific punishments in Episode 4 are not detailed extensively, the episode continues the show's format where Jimmy Carr issues challenges or punishments via cards to contestants who laugh or break rules. The episode features moments where contestants receive yellow cards for laughing, contributing to the competitive tension.