Chapman notes that even during filming they would rehearse sometimes more than 20 times before rolling. If the weather conditions weren't right, they'd spend that downtime running scenes, nearly constantly in movement. "We should have had like a pedometer or something," MacKay jokes.
The shoot also required its performers to participate in entire filmmaking process. During one sequence, set in a German bunker, Chapman and George were in possession of the only light source, essentially serving as assistants to famed cinematographer Roger Deakins in capturing the atmosphere. "Roger would be very good at giving us notes and we would have to be very specific on what we were pointing at to light what the camera was seeing," Chapman says. When the detailed choreography went awry, that was often incorporated into the final product. Such was the case of the climactic sequence wherein MacKay makes a mad dash amid exploding bombs as his fellow soldiers are going over the top. "When some sort of mistake happened we had to give it a real life and energy," he says. "When I get knocked over a bunch of times that was just what happened. But everyone was just like we do not say stop until someone says stop."
For Chapman, the intensity of the environment made his character's ultimate fate, a shocking demise midway through the action, more emotional. The moment in which Blake is unexpectedly stabbed after trying to aid a downed enemy pilot is the only one Chapman didn't rehearse. "As an actor, these continuous takes really allow [you] to just become fully immersed in what you're doing," he says. "I know this sounds stupid, but I genuinely believed I was dying. When they called cut, I'm serious, I couldn't stop crying." With Blake's journey left incomplete, Chapman felt his was too. "I literally got so lost in it I was living in it rather than acting," he says. "It was a weird experience."