What is it really like to be in northern Syria when the bombing starts? Few people are better equipped to tell you than Feras Fayyad, whose documentary “The Cave” is set in a hospital hidden underneath the streets of the besieged area of eastern Ghouta, where residents are afraid to leave and possibly doomed if they stay. Fayyad, who is Kurdish, shot mainly between 2016 and 2018, but says the dire circumstances are echoed in other embattled Syrian regions, right now.

“The ‘cave’ is the system used by medical societies to move hospitals underground after the Russians entered Syria and started using heavy bombs in the cities,” says the 35-year-old Fayyad on the phone in New York, where he’s promoting his film and trying to raise awareness of what’s happening in his native country.

In “The Cave,” Fayyad — an Oscar nominee for his 2017 documentary “Last Men in Aleppo” — shows a society straight out of dystopian science fiction. A handful of doctors and nurses live in tunnels underneath a bombed-out hospital, rarely leaving, using severely limited resources to tend to bloodied victims who stream in after the shriek of warplanes overhead, followed by explosions.

The medical team is led by a 30-year-old pediatrician, Dr. Amani Ballor. In a society where gender roles largely remain antiquated, she encounters men who question — even as she’s treating their children — why she’s working and not at home. “She’s painting a picture of a different kind of woman than they usually see,” says Fayyad. “She’s an independent woman. And she has to take care of all these people. She can’t break down or get angry, or she will lose a lot of control. She has this reaction of quiet and smoothness.”

Very occasionally, Fayyad captures Dr. Amani — as she’s called in the film — and the resident surgeon weeping quietly in a side room, despairing there isn’t anything they can really do. They have little access to medicine, antibiotics or anesthetics.

The sobering documentary is a testament to the bravery of medical professionals who’ve chosen to stay in the face of overwhelming danger. Fayyad says he tried to accurately represent how terrifying the sound of warplanes is, but that it’s simply not possible. “If I made it 100 percent real, nobody could take it,” he says. “It would destroy your hearing. We’ve compared it to ‘Game of Thrones,’ where a lot of people talk about the sound of the dragon. It’s the same with the warplane. When it’s coming, you feel like a monster wants to eat you.”

Fayyad, who now resides in Copenhagen, Denmark, with his wife and daughter, was also risking the possibility of another stint in prison: He’s already been jailed twice, once for 18 months, for his filmmaking. “I was taking footage of the Syrian demonstrations in 2011 inspired by the Arab Spring,” he says. “And then I was arrested. They hung me by my hands on the wall, they made me stand for 24 or 48 hours straight. They used electricity on various parts of my body. I witnessed a lot of people dead from torture. They made us move the bodies. Sometimes I wake up — like in this New York hotel today — and still can’t believe I survived.”

Despite the risks, he was determined to bring the world’s attention, again, to the ongoing situation in Syria. It wasn’t easy to bear witness. “I told my team, ‘Try to look directly through the monitor of the camera, not outside it.’ It makes it easier because the frame is small,” he says. “But it’s very difficult. These are our people, our city, in front of us. Our mission was to get the footage outside. And Dr. Amani was an extraordinary subject. When we thought we were going to break down, we would think of her.”