Heather Graham was a bit “nervous” before filming They Will Kill You, which required more stunt work than any other movie in her catalog.

The 56-year-old actress plays a cult member in the upcoming action-horror film, which sees her and costars Zazie Beetz, Patricia Arquette and Tom Felton embroiled in a bloody battle across a nine-floor hotel inspired by Dante’s Inferno. The high-intensity role required the “most amount of stunts” Graham has ever done before, she tells PEOPLE.

Though Beetz, 34, sees the most action in the lead role of Asia Reaves — and therefore required an intense stunt training schedule — Graham also had to practice daily before playing Sharon, a satanic cultist.

Recalling her training, Graham tells PEOPLE, “I mean, obviously [Beetz] has more, but I had to be there a few weeks early. I trained every day. It was hard, you know? It was hard.”

There were nerves at first, the Boogie Nights star admits — but they ultimately turned to elation.

“I was nervous because this was the most amount of stunts I’ve ever done,” Graham says, “but I felt very excited at the end just to feel like, ‘I love doing stunts.’ It was kind of exciting. It’s a little bit scary because you’re just like, ‘Oh my god, I hope they don’t hit me and I hope I don’t hit her,’ but it was really exciting.”

They Will Kill You takes cues from Quentin Tarantino and Sam Raimi (whom director Kirill Sokolov tells PEOPLE is his “North Star”) and employs both CGI and practical effects. Many of the latter are funneled through Graham’s character — including a memorable scene involving a lone eyeball, detached from its socket.

“I mean, my character gets put through some real s— in this movie,” Graham says with a laugh. “But it was really fun.”

“I think the eyeball thing is turning into a really fun moment, and last night at the premiere [at SXSW], they had a fake eyeball crawling around and we all took pictures and they gave out these eyeball key chains to everyone,” she continues. “So I’m glad I got to do action sequences and got to be part of so many crazy wild special effects things.”

Filming They Will Kill You was intense for much of the cast, but especially Beetz, who takes on her first lead movie role as Asia, a young woman fighting to survive a night at Virgil, a cult-run hotel in New York City.

Arquette, who plays a Virgil employee reminiscent of her stern Severance role, tells PEOPLE that Beetz’s time on set was like “a constant marathon,” and praised the actress’s “incredible amount of stamina, incredible amount of commitment.”

Graham, meanwhile, recalls how costar Felton would attempt to put a smile on Beetz’s face after her long, intense filming days. The Harry Potter alum, who also plays a cult member in the movie, would bring his ukulele to work and serenade the lead with “a song about joining a cult,” she says.

“He was trying to entertain Zazie, who was really tired,” adds Graham. “Obviously, she has so much action, but he was singing the song like, ‘The cult’s not that bad. Just join us.’ ”