Want a darkly funny and violent movie about a bunch of people shooting at each other in an deserted warehouse? Free Fire is the movie for you.

With an all-star cast including Brie Larson, Sharlto Copley, Sam Riley, Armie Hammer, Cillian Murphy and more and directed by Ben Wheatley, the premise is simple. Set in the ’70s, a handful of criminal types gather at warehouse for a gun deal, but things go south and escalate quickly. Suddenly, everyone is taking cover and trying to survive – not only from the flying bullets but also from their own arrogance and ego in thinking they’ll be the last one standing.

At the recent press day, ScreenPicks spoke Copley, who portrays the gun dealer, Vernon, and Riley, who plays one of the drug-addicted thugs driving the truck, about making the indie, the dangers of gun play on set and what it’s like being set on fire.

On being high in a gun fight:

Sam Riley: That was a weird morning. On the list. What am I doing today? Costume fitting and then they gonna show me how to chase the dragon. It tasted disgusting by the way.

Sharlto Copley: There are a lot of stories about that. Guys having to take drugs to deal with what we send them into and then we sit and judge them from the outside. You shouldn’t use torture. Fuck you we have to shoot up with cocaine and go kill people. We’ll decide if we use torture.

On coming up with their character’s backstory:

Copley: You know people ask about this. I don’t do usually. I don’t do an enormous amount like external sort of research of like, oh my character came from this, his dad did that to him. And blah blah, like some actors are, he eats this food. I have a diet. But I just sort of energetically hook into something and then work from there. I work from a voice, I work from the deepest place that I can with the character rather than the … So in this case I had a great point from Ben and Amy in the script of like Vernon was misdiagnosed as a child genius and never quite got over it. I can see what that might be emotionally.

And then kind of exactly where he went to school or whether he was on the football team or not, is not as important as, okay how would that have translated. Probably he would have always been pissed. Then you could ask me like how was school for you? I’ll tell you from that point of view. I have no problem, you could ask me as Vernon. If you ask me now, it’s like I have to try to think about it. If I’m being Vernon and you ask me about school or my mom or my dad. I have no problem telling you about them.

Riley: I think I’m similar. We were still talking about this earlier, how both of our wives actually quite …

Copley: Loved our characters.

Riley: I don’t know what the redeeming qualities. You even feel sorry for him though, my wife was saying that, so at one point I was like wow, okay.

On ducking and crawling through the debris and rubble:

Riley: It’s uncomfortable to some extent, but we were all in it together, there wasn’t really … You couldn’t really …. You could only complain on it to the phone to somebody later at night. You could never complain in front of the others.

Copley: Everyone has to just toughen up.

Riley: But other than that, we got in such a specific type of mess that it could only recreated by just lying on the ground, rolling around or putting your head in a pile of dirt. That was the only way of replicating the continuity. Putting the wet jeans on every morning. It was like sticky as hell.

Copley: From the blood.

Riley: From the blood, yeah. Not from peeing myself.

On being pretending to be set on fire:

Copley: That was, as it turns out, insurance believes that’s the most dangerous thing I have ever done on camera, because insurance insisted that be done after they have shot the whole movie. If you are looking mathematically at odds of dying apparently according to insurance company anything I’ve done since would be prior was not as dangerous requesting I be set on fire, we also may have to jump out of a van so we also may need to get some van insurance just in case. Because everything else was shot in sequence. And that did start to kinda freak me out just a little bit. I was like really, okay? Do you still want to do. Yeah I’ll still do it, because now I’ve acted like a tough guy until that moment.

But actually what got me with that was, they did incredible prosthetic work on me. I mean like third degree burns on my arms and you see some of it in the film, but really we don’t linger on it enough. The actual whole back of my head is burnt and the shoulders are burnt and the arms and the suit is burnt into the flesh and it was so realistically done and so I was doing post burn before I actually set myself on fire.

I was doing the scenes where I had this on, sometimes you know what I’ve experienced in acting is, you’ll do something and this was one of those cases, where it was so realistic that as I moved the tendons in my hand, these burnt tendons with 3D burns would move and your brain is trying to process it. Your brain is going, “I’m burnt, but I’m not burnt.” A few times my hand would just start to shake like this. I would be like what the hell is going on. So I didn’t make it easy for myself, because I also had a set medic who had worked with real burn victims. He was like, he’s been in war zones. And so I thought it was a great idea to get him in to come and see how realistic is this. And then he started telling me stories and I would be like, if I accidentally burnt, you know and I had some gas or this glue like they’re putting on my hand and the degree burns.

I wouldn’t burn like that easily right? He’s like, “No man you’d be … Once the fire sets a light, you’d be there in about five seconds. You know, like burn down to that amount.” So he would explain to me how easy it is for me to get to that level of burn if it was to go wrong. Suddenly, I’m like, he’s not telling me stories about like, you know, there was this one guy at a petrol station and he caught a light and he is telling me the whole story about he had to go and all these horror stories which I am sort a fascinated by in one way, but then the day is coming when I have actually set myself on fire. It just kinda mentally messed with me.

On laughing a lot between takes:

Riley: There is a lot of laughter, but we’re just talking about this in a previous interview, but there wasn’t any corpsing, which is when you laugh on during a take. It was usually, it was between there was a lot of it, but there was always an element of anxiety before every take.

Copley: Once the shooting started.

Riley: Because of the gun fire and there was always a sense with me certainly, at the end of each day that everyone was all right. It was the most … For me as well the most dangerous set in the sense of what could have happened.

Copley: The number of charges that I was saying to someone, I think it was probably by quite a way the most dangerous in terms of like number of squib hits that were right by my head at a given time, that were loaded at that time, because Ben would do long takes, so normally into something, you would have like, okay, we’re gonna do the shot where I get … Someone shoots at me and I would move off the chair and then the squibs blow up and we do three of those, but in Ben’s thing like, we do all of our chairs and then we do the sequence, a guy comes in and starts shooting and we all going to the ground and so, if you get the timing wrong with any of that stuff, the charges are gonna go off right next to you and then it absolutely will damage you. It’s not gonna … And if it goes by your face.

On how the set was behind a supermarket:

Riley: It had been industrially cleaned in order for it be made filthy. It was right behind the supermarket in Brighton [England]. We used to dare each other to go in and buy sandwiches. There was a brilliant sign outside the supermarket. It was sort of telling people not to call the cops.

Copley: They put the sign there on the first day. So someone called the cops, so the cops arrive and it was a whole thing, because when there’s gunfire in England and the police come with the gun … Police come, that’s the whole thing.

On the balance between the dark comedy and the violence:

Riley: I think that developed as we were doing it. I remember the very first version of the script that I read, it was funny, but it wasn’t … It was grim as well. It started to develop as we were doing it and this fantastic process of improvisation mixed with a brilliant script and flipping between the two things and then Amy [Jump], who’s Ben’s partner and writer, she’d also starts to tailor. You’d get rewrites very often and they’d be tailored more to how she saw us taking over the … You know how the character was developing in the hand of the actor. It got funnier. It would be a pretty grim film if it wasn’t funny.