"Dignity and indignity is great comic fodder, and that's what we're dealing with in this situation," says Flack.
"The endless worthiness of the discussion around these issues is ineffective. And this notion around refugees, that they have to be either demons or saints, is really ineffective.
"Because refugees are as idiotic and ineffective as the rest of us when it comes to waiting in a queue. I've seen people behave like morons in a queue at the box office in Belvoir Street. It's the unifying humanity of being idiots is what the play is about."
Flack is directing the bold comedy, a free-wheeling affair about a man who, in an attempt to find answers to some of the big questions in life, becomes the camp hero and almost sparks a revolution.
It is based on Russian playwright Nikolai Erdman's 1928 play The Suicide, a comic drama about a man whose decision to kill himself is hijacked by those around him.
In a lunch break during rehearsals, Flack and stars Yalin Ozucelik, who plays Sami, and Charlie Garber, who plays a small-time aid worker called, well, Charlie Garber, say they hope that by turning a divisive topic such as refugees into a comedy, it can soften people's attitudes to the their plight.
"If you can do something that's entertaining, funny or inventive, then you definitely are going to get better mileage than tut-tutting or self congratulation," says Flack.
"It's a great question about how much anything can be achieved through art," adds Garber.
"I don't know if anything gets changed by a piece of theatre. I have no surety that it does. But there is some sense that it still needs to happen. You just have to stake that pole in the ground.
"When you are involved in a play like this, you don't want to come in too hopeful, because that nearly turns people away, But that doesn't mean you shouldn't do it, and not look hopefully at them, and then they might come to the idea themselves."
Ozucelik says: "Having conversations on a large level, or different types of conversations on a particular topic is important, and theatre is one type of discussion."
The three have a long history at Belvoir together, though Garber is surprised to realise he hasn't worked with Flack since the company's 2011 production of As You Like It, while Flack and Ozucelik most recently worked together in 2016's The Great Fire.
Adding another layer to that relationship was the writing of Sami in Paradise, which Flack co-devised with the cast of 11. And while the bones of Erdman's The Suicide did much for setting up the comic logic of the play, Flack was keen to work with the actors to develop the new story.
"On other things, you just kind of want to shut the world out and live with the play," he says. "But in this instance, I wanted it to be as shared as possible and as open as possible to the influences of the research and the particular view of everyone in the cast."
Even if those ideas weren't always welcome.
"You have to be genuinely prepared for a no and for it not to matter," says Garber.
"But also vice-versa," adds Flack. "Sometimes these guys can look at what I've written and go, 'I don't think this works'. Rigour is normal, especially in comedy."
The trio's familiarity added immeasurably to the development of the play but it didn't help the director across every hurdle.
"The weird thing was that I knew how to write for Yalin, but I didn't know how to write for Charlie," says Flack.
"In the end, we wrote your stuff together. The character was a bit of an enigma still. It wasn't until you decided that he should have a South African accent that I thought, 'Oh yeah, I know where we are going with this.' "
A South African accent? Isn't that veering into dangerous Leonardo DiCaprio territory, with his questionable accent in Blood Diamond?
"I've got more leeway in this comic show than Leonardo DiCaprio had on the world stage in a drama," says Garber, laughing. "I have South Africans in my family, so it's an accent that's been building up for a while."
Sami in Paradise is at Belvoir Street Theatre from April 1-29.
Louise is the editor of S and the Sun Herald's TV liftout
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