into theirs and it mustn't jar, it must fit in exactly so no-one can tell the difference." Brett Ratner, commenting about Conrad Palmisano, who directed second unit for Ratner on Rush Hour 3 and After the Sunset, said, "He has the understanding of what it takes to create a great action sequence and never deviate from the story or the tone of the film." Because second units often film scenes with stunts and special effects in action movies, the job of stunt coordinator is often combined with that of second unit director. Many second unit directors were stunt coordinators first, including Vic Armstrong, who has directed second unit on The Amazing Spider-Man, Mission: Impossible III, and War of the Worlds; Simon Crane, who did Men in Black 3, Frankenstein, and X-Men: The Last Stand; and Terry J. Leonard, responsible for second unit on Cowboys & Aliens, The Expendables, and Die Hard with a Vengeance. Second unit director can be a stepping stone for aspiring directors to gain experience. Unlike an assistant director, who is second-in-command to the main director, a second unit director operates independently. Second unit directors who have gone on to become full-fledged film directors include former editors Peter Hunt (Goldfinger), John Glen (On Her Majesty's Secret Service), stunt coordinator David R. Ellis (Final Destination 2), and Frank Marshall, who directed second unit for Steven Spielberg whilst also working as producer, on Indiana Jones and the Last Crusade, Empire of the Sun, and The Color Purple. Some who became directors may return to working predominantly as second unit directors for the remainder of their career. Notable examples include Yakima Canutt (Ben-Hur, 1959) and Michael D. Moore, who worked on more than sixty films, including Butch Cassidy and the Sundance Kid (1969), Patton (1970), and the first three Indiana Jones films in the 1980s. It is common for certain personnel involved with a production in another capacity to also function as a second unit director, benefiting from their understanding of the material and relationship with the production's director or producers. For example, English actor Andy Serkis, who plays Gollum, was second unit director on Peter Jackson's three-part adaptation of J.R.R. Tolkien's fantasy novel The Hobbit. Actor George Peppard, whilst the star of the detective drama Banacek, also served as second unit director for several episodes of the series. A notable exception to having more than one filming unit is