destroyed, involving work with explosives and an unusual reliance on special effects. Ridge later commented that she had "felt quite guilty" about the Liberators demise, adding that "Battles and explosions are a director's heaven, and they're terribly exciting when they work." Alan Stevens and Fiona Moore describe the episode as among "most postmodern and allegorical" of the series; the scenes on the planet with Avon (Paul Darrow's character) are accompanied by an "ominous heartbeat-like sound", which Stevens and Moore compare with "The Tell-Tale Heart" by Edgar Allan Poe. "Terminal" had viewing figures of 10 million, and Stevens and Moore credit the show's renewal for a fourth season to the enthusiasm of Bill Cotton, then the head of BBC Television, for this episode. Ridge became a regular director for season 4, and had input into the design of the set of Scorpio, the crew's new ship, suggesting, for example, the insertion of trap doors to allow more variety in camera angles. She directed five episodes of season 4, including the season opener "Rescue". Her direction of "Headhunter" gained praise from Stevens and Moore; the critic John Kenneth Muir writes that the android's attack sequence is directed "with aplomb, never allowing the pace to slow down once the attack has begun." Her most notable contribution, however, is the final episode, "Blake", in which Gareth Thomas returns as Blake, only to be shot dead by Avon, and then almost the entire cast apparently die. Ridge stated in an interview that she had been given considerable leeway over the way in which the final shootout played out; she made Avon killing Blake the focus, and decided to film the final scene in slow motion to give it a "slightly unreal feeling", to allow for a subsequent season, which was not commissioned. Stevens and Moore consider "Blake" to be perhaps the show's strongest episode; they compare the shootout sequence to the classic western, The Wild Bunch, and the final freeze-frame with Avon still standing and shots sounding over the credits to Butch Cassidy and the Sundance Kid. The journalist Joe Nazzaro describes the episode as a "stunning cliffhanger" that guaranteed the show "a place in SF television history". Muir considers much of the show's reputation to derive from "Blake", with its "stunning and ultraviolent conclusion"; he adds that the decision to kill the cast members "infuriated legions of fans, but also cemented Blake's 7s reputation