Reality Winner’s life changed six years ago in June when FBI agents showed up at her home in Georgia. By the end of the encounter, Winner, who was then a 25-year-old former U.S. Air Force linguist, had been arrested, accused of leaking a top-secret report that included details of Russian interference in the 2016 presidential vote.

In 2018, she was imprisoned under the 1917 Espionage Act, a disappointing outcome for her family and some advocacy groups who saw her as a whistleblower who deserved better from the American democracy she’d stuck her neck out to protect. They maintain that Winner was repeatedly wronged, including by journalists whose actions provided clues to her identity and by federal agents who they say questioned her without first reading her Miranda rights.

I’m giving this background because Tina Satter’s gripping docudrama “Reality” doesn’t. Satter strips the political context from that first FBI interrogation to present a study in social dynamics: one awkward young woman (Sydney Sweeney) and the two placid inquisitors (Josh Hamilton and Marchánt Davis) who’ve isolated her in a backroom to distract her with chitchat about CrossFit while other agents comb through the house. Winner does not realize her peril. Working from the official transcript, Satter finds that the young woman is primarily concerned with the safety of her pets. “Can I close the door for my cat?” she asks. “That’s all I care about right now.”

The banality is chilling. Satter has already staged this conversation, off-Broadway in 2019, and then on Broadway in 2021, with the show’s title, “Is This a Room,” taken from one of the transcript’s more absurdist quotes. Satter, a veteran theater director, makes a smooth transition into her feature film debut, written with James Paul Dallas. She’s skilled at evoking tension from a minimal set. Her lighting is intelligent and controlled — you sense Winner’s last free sunset slipping past through the windows — as the whining, almost mosquito-pesky sound design (Ryan Billia) and score (Nathan Micay) make your jaw clench. The new medium allows for a new flourish. Whenever the transcription stumbles across a redaction, the image glitches as the characters disappear into a poof of pixels, snapping back when someone says, appropriately, “Reality!”

Not every stunt works. When Winner imagines a fantasy in which she’s able to seize control, the personality shift that might have been successful within the boundaries of the stage loses impact once the scene starts cutting around. Detail-minded viewers may also notice that the movie has taken the liberty of altering two facts: It changes the weight on Winner’s driver’s license (but keeps her joke about fudging it) and, more mysteriously, gussies up her cat, trading her black shorthair for a fluffy white princess. The smartest adjustment, however, is in how the talented Sweeney delivers her lines. Her Winner is no longer jittery, or nervous. Now, she’s watchful and charming, even while fighting not to flush. She’s a good little soldier.