"As a whole, we wanted to keep it as grounded as possible, even from a casting point of view with Martin, who has such a subtle, interesting and unpredictable approach to his work. His presence grounded the film. With the zombies, we wanted to keep them peripheral as much as possible. We were concerned with that balance of how far can we push that? Can we keep the Virals on the sidelines? What’s the tipping point of what you actually need to show? When do you raise the stakes a little bit? But just always keeping it about the people."