Before Shaun and Ed leave the house armed with their Winchester-centric plan, Shaun checks if the coast is clear by looking out of the letterbox. Ed asks him if there are any zombies out there, and Shaun objects to the Z-words usage despite the fact these clearly are the walking dead. This is seen as a reference to two things firstly, in most iconic zombie movies such as Night of the Living Dead, they never use the z-word. However, it can also operate as a sly dig at 28 Days Later, which director Danny Boyle insisted wasnt a zombie movie. This can be confirmed when Shaun is checking the TV channels at the end of the film, where a voice provided by Wright claims rumours the epidemic was due to rage infected monkeys have now been dismissed as b, showcasing an obvious crack at Boyles film. The joke comes back later in the Winchester when David keeps using the word, to Shaun and Eds discomfort.