Who’s ready to take on a ton of pressure? Director Kathryn Bigelow and screenwriter Mark Boal certainly must have been. Not only did Bigelow and Boal have to follow-up their Academy Award-winning work in The Hurt Locker, but the pair chose the most challenging material to do it with – the hunt for Osama bin Laden.

Forget all the required research, possible political scrutiny and delicacy of the material; making the project even more demanding, bin Laden was actually killed just a short while before Boal completed his script detailing the failed hunt for bin Laden in the Toro Bora mountain range.

While participating in a press conference in New York City, Bigelow recalls, “While Mark was working on the screenplay, actually quite far along in the screenplay, May 1, 2011 happened and we realized, after some soul searching, that it was going to be a little difficult to make a movie about the failed hunt for Osama bin Laden when the whole world knew that he had been killed.” And so the plan changed and Boal refocused his script on the raid on bin Laden’s compound in Abbottabad – the raid that ultimately resulted in his death.

Even with a very specific event at the core of the film, much of what we see in Zero Dark Thirty was never preconceived – rather the story organically presented itself during Boal’s research. Like for many, Boal calls 9/11 a very personal day, pointing out, “I was born and raised in this town.” However, even with those personal stakes, he also insists that he didn’t approach writing this script with an agenda. “I didn’t know what the story was gonna be when I sat down.” The characters in the film are based on real people because “that’s what emerged from the reporting. It could have been something else. Whatever it would have been is what I would have tried to piece together.”

And so, with these very important people at the heart of the film, in came actors like Jessica Chastain, Jason Clarke and Kyle Chandler. Of the opportunity to join the cast, Clarke, who plays the unfettered interrogation specialist, Dan, proudly proclaims, “These things come along once in a lifetime. Touch wood.” After a quick tap on the table, he turns back to clear up any misunderstanding and laughs, “I mean touch wood yes and no it does happen and it doesn’t happen.” Chandler who portrays Joseph Bradley, the CIA Station Chief in Islamabad, joins in for another lighthearted response, “I have a lot of military friends, so when I found out I was doing this, I was like, ‘Guys, guess what I’m going to do.’” The audience laughs and Chandler chimes back in, joking, “And they laughed like you did.”

Chastain was in New York City during 9/11 and when bin Laden was killed, but she admits, “When I was reading the script, every page that I turned was a shock to me, especially Maya and the role she took in it. And then I got upset that it was such a shock to me. Like, why would I assume a woman wouldn’t be involved in this kind of research?” Somewhat answering her own question, Chastain points out, “Historically, in movies, lead characters are played by women defined by men, whether it’s a love interest or they’re a victim of a man, and Maya’s not like that.”

Naturally, the press conference audience is itching to find out who the real Maya is, but Boal is quick to point out, “One of the things just as a general life principle we’re not gonna do is talk about the real life people that the film is based on, because many of them are still working and we take protecting their identities very seriously.” Real-life Maya wasn’t only out of bounds to the press; Chastain wasn’t even given the opportunity to meet her. However, she does note, “I got a lot of research from Mark. It really helps when your screenwriter’s an investigative journalist.” She adds, “Questions that I couldn’t answer through the research I then had to use my imagination and Kathryn’s imagination, and Mark’s to create a character that went along the lines that respected the real woman.”

Chastain mentions coming up with Maya’s favorite American candy for when she’s homesick and her music of choice, but doesn’t elaborate. In fact, she seems proud to have an understanding of that type of information, but on a personal level, so nobody pries. Still, Chastain has a great deal of insight to offer on a more visceral level. “When I was doing my research and I was thinking about her, I was thinking about her as a computer almost, a woman who’s really good with facts and details, and putting a puzzle together.” But, just like computers, this woman who was plucked straight out of high school to become a prime player at the CIA, was subject to, well, crashing. Chastain continues, “Just because she’s trained to be unemotional and analytically precise doesn’t mean she’s unemotional, and what I loved so much about the script is we do see moments where she falters.”

In fact, one of Chastain’s favorite scenes is one during which Maya shows some vulnerability. “It’s very hard to play something that is subtle and specific, and really tiny in the arc, so it’s really fun to play the scene where I’m chewing out Kyle in the hall.” While the moment shows a Maya who is as hell-bent as ever to get the job done, she ultimately winds up blackmailing her boss, a major no-no that arises not from her analytic prowess, but from her honest emotions.

Strong feelings consume Maya and Chastain herself through one of Zero Dark Thirty’s more controversial sequences, the depiction of the severe torture tactics used to extract information from a prisoner played by Reda Kateb. Chastain admits that portion of the shoot was particularly tough, but also recognizes that “It’s a part of the history of the characters and instead of looking at it and making my own judgments on what I personally believe is right and wrong, I try to look at it in terms of the character.” She continues, “[Maya] shows up in her suit to go to what she believes is gonna be a normal interrogation. It becomes much more intense than she imagines.”

As the one playing the main man in charge of dishing out this brutal treatment, Clarke agrees with Chastain, “Without the honesty and the integrity of that sequence, you’re not gonna feel the weight of the end.” He adds, “I know for myself and Reda who shot the scene, we were grateful. Reda’s a French-Moroccan actor and he was grateful to get in there and explore that part, and then show this story as we know the facts demonstrate.”

Even with integrity being the driving force behind these scenes, there’s really no avoiding a degree of scrutiny and both Boal and Bigelow are well aware of it. Bigelow admits, “There’s no question that that methodology is controversial, but there was no debate on whether or not to include it in the movie because it’s part of the history.” Rather than deciding whether or not to show the torture, Bigelow explains, “It was really a question of finding the right balance.”

Even with the torture scenes being the most disconcerting, as the piece progresses, tensions run higher and higher until they explode in the film’s most moving moment. No, not the actual killing of Osama bin Laden, but rather Maya’s reaction to his death. Bigelow explains, “I think what’s so interesting and so poignant for Jessica, myself, for all of us, is this idea that this woman has spent the last ten years exclusively in the pursuit of one man and yes, at the end of the day, she triumphed, but it’s not a victory because finally, at the end of the day, you’re left with much larger questions like, where does she go from here? Where do we go from here? Now what?” Chastain adds, “I find that to end the film on that question is far more interesting than providing an answer.”

Considering Maya’s story isn’t wrapped up neatly and the weight of the material in general, it isn’t surprising that Chastain wasn’t able to simply snap out of Maya mode. Not only were the filmmakers constantly immersed in this world having shot the film in Jordan and India, but Chastain took it one step further, recalling, “I had the props person print out all the pictures of the terrorists that Maya looks at and I actually hung them in my hotel room, so even when I would come home from set, it was always around me.”

For someone who describes herself as “a very emotional girl and very sensitive, I like to have a good time, I’m very smiley,” living in the world of a far more solemn and composed-to-the-extreme character like Maya is a major change for Chastain. However, the two do find common ground through their devotion to their jobs and it’s that devotion that encourages Chastain to shake off a day of talking Zero Dark Thirty and hit the stage as Catherine Sloper in The Heiress. Chastain explains, “I can understand that passion and servitude, some might say, not quite to the extreme that she does and I’m nowhere near the amazing woman that Maya is, but I do understand that and that’s what gets me on stage every night.”

Yes, Zero Dark Thirty will likely make a pretty penny at the box office and go on to accumulate a number of accolades, but it’ll have a much longer lasting effect than even the best of the best. Boal notes, “It’s been a decade that in a lot of ways was shaped by 9/11,” and, in turn, what Chandler points out will most likely be the case, “I think that this is one of those movies that ten years from now, you’ll be able to look at it again and go, ‘Yup, that was my time. That was our time.’” Zero Dark Thirty is a movie and a movie is meant to entertain, a feat Boal and Bigelow were able to achieve because, as Boal says, “the material’s inherently dramatic,” but sheer drama and entertainment isn’t all Zero Dark Thirty has to offer. Bigelow explains, “My hope is that some of those more difficult images can be replaced and/or that narrative can be amplified by another narrative, one of courage and dedication, and a kind of nod to those men and women who work in the intelligence community to try to make our lives safer.”

Follow Perri on Twitter @PNemiroff.