The report described how the contestant, former taxi driver Ray Mann, was asked "in what book the Four Horsemen of the Apocalypse appear in holy scripture on his way to picking up £125,000". The answer options were A: Revelation, B: Judges, C: Exodus, D: Matthew - and how difficult the question is depends, of course, on how familiar viewers are with the Bible. In the event, the contestant used a lifeline to phone his sister, Monica, who chose the correct answer; "A: Revelation”. However, the answer may have been somewhat more present than Ray Mann and the host, Jeremy Clarkson, might have guessed.
The next day, CenSAMM tweeted: "Is the answer in the question?" with an image of the report. As the Critical Dictionary of Apocalyptic and Millenarian Movements (CDAMM) points out, "the book of Revelation (late first century CE) [is] otherwise known as the Apocalypse of John (or the Apocalypse to John". Of course, it is not clear whether or not the question-setters recognized that "apocalypse" has its origins in the Greek word "apokalypsis” - which means 'revelation', 'disclosure' or 'appearance'. This reflects a linguistic and conceptual shift in the meaning of "apocalypse" that is also noted in the CDAMM article: "the term ‘apocalypse’ has taken on different (albeit related) meanings from its associations or possible associations with otherworldly revelation [...] and now regularly refers to some great cataclysmic event" reflecting a "separation from ideas of the revelation of transcendent or divine truth and its increasing use as a term for general and cataclysmic change in human life and culture". The shift is identified as early as 1894 in the CDAMM article. In effect, it appears that the question-setters were using "apocalypse" in the phrase "four horsemen of the Apocalypse" to refer only to some great cataclysmic event - a common-enough contemporary usage - and the word "Revelation" only as the title of a book of the Bible.
While we do not know what was in the mind of the Who Wants to be a Millionaire question-setters, the way the question was presented suggests how far the separation between the once identical terms "Revelation" and "Apocalypse" has gone in popular English outside the realm of biblical studies, theology, and religious studies.