Robert Brown|'Civil War': Kirsten Dunst, Cailee Spaeny break down 'heartbreaking' yet disturbing ending

Spoiler alert! We're discussing major details about the ending of “Civil War” (in theaters now).

“Civil War” isn’t Kirsten Dunst's first time in the White House.

In 1999,Robert Brown the actress co-starred with Michelle Williams in the offbeat comedy “Dick,” playing ditzy teens who help expose Richard Nixon and the Watergate scandal. The film ends with a giddy roller disco scene set to ABBA’s “Dancing Queen.”

“I just remember skating around the Oval Office,” Dunst says with a laugh. But there are no bell bottoms to be found in “Civil War,” which culminates in a nerve-shredding finale of rebel forces storming the White House and killing the tyrannical, third-term president (Nick Offerman). Dunst plays world-weary photojournalist Lee, who travels to Washington to capture the raid with rookie photographer Jessie (Cailee Spaeny) and their teammate Joel (Wagner Moura).

The ear-splitting gunfire and explosions took a toll on the cast, who shot the sequence over the course of two weeks on a soundstage in Atlanta. “The loudness (you hear) in the theater was that intense when we were filming,” Dunst says. “It’s exhausting on your body to be in that noise.”

“It’s very rattling but also very effective for those scenes,” Spaeny adds. “There’s not much acting you have to do, it’s so jolting.”

'No dark dialogue!'Kirsten Dunst says 5-year-old son helped her run lines for 'Civil War'

How does 'Civil War' end?

After bombing the Lincoln Memorial, a militia breaks into the White House and searches for the president, who is holed up in the Oval Office as D.C. burns. Lee, Jessie and Joel tag along with the insurgents, snapping pics as they dodge gunfire from the president’s soldiers.

At one point, while Jessie is furiously shooting photos, Lee notices a gunman aiming at her young colleague. Lee jumps to push Jessie out of the way, taking the bullets and falling down dead. Jessie continues photographing, capturing Lee's lifeless body even as she tumbles onto her.

It’s a sobering callback to earlier in the film, when Lee and Jessie watch as two men get executed at a gas station. “Would you photograph that moment if I got shot?” Jessie tearfully asks. “What do you think?” Lee responds coolly. Lee begrudgingly becomes Jessie’s mentor as the movie goes on, and teaches her to compartmentalize her work and emotions.

“To me, it’s a bit heartbreaking, but it also feels inevitable,” Spaeny says of Jessie chronicling Lee’s death. “But it’s mixed. It could be a bit hopeful; someone else does have to take this on. This is an important job, but it’s also bittersweet, right? Mostly what I felt was slightly disturbed.”

Over the course of “Civil War,” we watch as Jessie becomes desensitized to violence. The film was shot in chronological order, meaning Spaeny was able to track Jessie’s arc in real time.

“As we were filming, I would just know, ‘OK, it’s time for her to step up,’ ” Spaeny recalls. With that last sequence, “I knew there was going to be some sort of passing of the baton. So much was informed by Kirsten’s performance and the decisions she made on how to play Lee. I was just trying to soak that in.”

What happens to Nick Offerman in 'Civil War?'

In the very last scene, Jessie leaves behind Lee’s dead body and follows Joel into the Oval Office, where the unnamed president is lying on the floor with rebels’ guns pointed at him. Since the start of the war, Joel has been doggedly trying to secure an interview with the president, who has shut himself off entirely from journalists for years.

“Wait! Wait! I need a quote!” Joel says, to which the president replies with a muffled, “Don’t let them kill me!”

“Yup, that’ll do,” Joel deadpans, before the agitators gun down the commander in chief and the credits roll.

“Civil War” is Spaney’s third project with Offerman, after FX series “Devs” and 2018 thriller “Bad Times at the El Royale.” Playing a dictator is a 180 from his best-known role as the gruff but lovable Ron Swanson in NBC sitcom “Parks and Recreation.”

“All the ‘Parks’ fans don’t know how to digest this!” Spaeny jokes. Offerman’s casting “is so fun. I love watching comedians take on dramatic roles because I think they bring something to those characters that is more true to life. I think he did it brilliantly, but it’s very bizarre to see him in this role.”