Because You Left - Production

Production

Following a writing "mini-camp" to map out the fifth season, the premiere's script was written and filming began on August 19. Show runners Damon Lindelof and Carlton Cuse wrote "Because You Left", and decided to put in the episode a setup for most elements of season 5, specially time travel. In order to avert implementing the time travel in a confusing way, the exposition of Faraday's theories was rewritten to start earlier and be more specific. While previous seasons had been filmed in high definition, this season premiere was the first Lost episode to be edited in it.

Lindelof stated that "When season five starts, you won't know when or where you are. And the way we tell stories will be different too", and confirmed that the "whooshing sound" effect will continue to be used as the transition for the new storytelling device. When asked if episodes continue to focus on specific and different characters, actor Jorge Garcia, who portrays Hurley Reyes, replied that "It's not as clear cut as it's been in the past. We don't have the moments where someone stares off into space and then we cut to something that happened in their previous life. They've gone in a slightly different direction as far as how they're telling the story and they're definitely trying to show what's going on with more people in every given episode." The script included scenes with all the main characters, including Desmond in the ending, because the writers felt that after a long break the audience would like to see every character again. Like the previous three season openers, the opening scene was meant to make viewers "not supposed to have any sense of where and when we are". But while the other premieres had the teaser connecting into the main plot of the episode, the writers decided to put a scene that would only return in the fourteenth episode, "The Variable". The time flashes were designed in a way that demonstrated both the castaways at the beach and John Locke in the jungle were "skipping" to the same time periods, and also to show that time travel was painful for the characters.

In regard to what Lindelof described as "the Zodiac boat with Faraday and the five people that have never spoken a line on show", executive producer/writer/show runner Carlton Cuse said that "I'd be a little bit more worried about the non-line speakers than Faraday", while Lindelof added that "things are looking up for Faraday" and "there is a monsoon coming." Regarding the background survivors in general, Carlton Cuse has responded that there is "a very tragic event that happens this season." According to Lindelof, Neil "Frogurt" (Sean Whalen), a background survivor who has appeared solely in the Lost: Missing Pieces mobisodes, "will rise up this season in the grand tradition of Dr. Arzt to let his feelings be known." Sawyer is shirtless throughout the episode. Cuse jokingly justified as that "for people who really couldn't grasp the time travel aspects of the show, there would be Sawyer without his shirt on for the entire hour." His actor, Josh Holloway, kept fit in the summer break before shooting and noted this as "really disturbing. Coming after a hiatus, that ain't fair!"