Screen time is a funny thing. Orson Welles steals The Third Man in barely 15 minutes, Pulp Fiction is dominated by Christopher Walken’s walk-on, and The Wolf of Wall Street takes more than two hours to never recover from a blazing cameo by Matthew McConaughey.

Which brings us to Niamatullah Arghandabi. You’ve never heard of him before because he’s a policy adviser to the Afghan government, not the kind of guy who shows up on Jimmy Kimmel or your Twitter account. But actor-writer-director Paul Gross knew he had to tap the “unbelievably charismatic” nonactor when he was introduced to Arghandabi by a Canadian intelligence officer. Not long after, the former mujahedeen warrior was on-set, playing the critical role of a legendary fighter called the Ghost in Gross’s Canadian war flick Hyena Road.

“I never auditioned him,” Gross says, meeting the Straight at a downtown hotel during the Vancouver International Film Festival. “I just hung out with him in London for about a day and a half and listened to him talk. So he came in the day before his scene and I suddenly had this panic attack. What if he’s terrible? I rolled the dice on the whole film…” Gross pauses for effect. “And then I was just floored. I’ve really never seen anything like it.”

“We just felt so ridiculous,” adds Hyena Road’s leading man, Rossif Sutherland, joining his director. “You go to school and you train and you try to develop some proficiency at this thing that you have a passion for, and you think that maybe all this experience comes to your advantage. But we found ourselves in front of him, and I remember…it was hard for us not to become spectators, you know, and just be in awe.”

Arghandabi more than pulled it off, in other words, and not just in front of the camera. Gross chuckles as he remembers his Ghost schooling an incredulous gun wrangler, taking “about 12 seconds” to strip down an AK-47. “He brought a gravitas to the longevity to the conflict in Afghanistan to everybody. It was real all of a sudden,” remarks the filmmaker, who was otherwise at great pains to authentically capture what he saw in Afghanistan as he prepared the film. Up to a point, at any rate.

“I wasn’t allowed to shoot stuff that would in any way, shape, or form compromise operational security,” he explains. “We weren’t allowed to shoot the strip at Kandahar airfield in relation to any structure that the enemy could then use and triangulate to try and fire a rocket. But apart from that, nobody ever asked for creative control or approvals. In fact, no one asked to even read the script. And I think it’s because the Canadian Forces seem to believe that if you just come in and see what we do, you’ll be impressed with how we go about doing it, and, indeed, I was.

“It’s not that I ever set out to be a war filmmaker, ’cause my interest in the First World War was really just a personal interest in my grandfather’s life,” he continues, referring to his 2008 effort, Passchendaele. “But in this one it really had to do with meeting soldiers. What are we asking them to do? They’re our fellow citizens and we’re like, ‘Go over there and fight for us, would ya?’ We have no sense of it.”

Inevitably, Gross has been criticized for the project. Hyena Road is cracking entertainment and genuinely moving, but it enters a moral quagmire for precisely those same reasons. He counters that art and war have orbited each other for centuries.

“Look, the first poetic document in western civilization is the Iliad, and it’s 24 long chapters of detailed hand-to-hand combat,” he reasons. “We start with that, and it’s never really left us, and there’s almost no period in history when we haven’t been fighting wars. I think to not look at warfare is as bizarre as you can get.”

Indeed, it’s to his credit that Gross looked hard enough in this case to see some of the deeper and less honourable politics behind the coalition effort in Afghanistan. Hyena Road hinges on the activities of a character based on Ahmed Wali Karzai, the real-life half-brother of former U.S.-installed president Hamid Karzai.

“Drug runner, child stealer, he was as filthy as they come,” in Gross’s words. “But nobody was allowed to do anything to him because he had the White House as a roof—and, ironically, it was only two days or something after we handed Kandahar to the Americans that he was blown up. So I guess they, too, had had enough of him.”

Still, Canada’s basic role in the conflict has been the source of considerable disagreement among Canadians. Hyena Road takes no position on the debate either way, and Gross defers entirely. “I don’t even have an opinion about the engagement in general,” he offers, “ ’cause I don’t know at which point you decide whether it was good or bad.” Which leaves an impassioned Sutherland to address the domestic rift that Hyena Road needs to somehow bridge.

“Seeing those soldiers when we were doing the screenings,” he begins, “we took no satisfaction in seeing how emotional they’d get, because you don’t want to make somebody cry. But they were extraordinarily proud to just have this story told, because they’re criticized by people who just don’t take the time to understand. Everything’s political, and rightfully so—you can judge whether or not it was right to go to war—but, ultimately, we’re sending these people, and they are people. And we can never forget that.”