In an interview with Rolling Stone, Rupert Grint talked about how much he likes working with Shyamalan, referencing the fateful day the director visited the set of “Harry Potter” and met Grint for the first time. He mentioned that when the director approached him about “Knock at the Cabin,” the pitch was “quite vague, which is kind of his style.” However, Grint knew that he wanted to take the role because the subject matter tackled his “biggest fears: the end of the world and home invasions.” The actor recalls the nerve-racking incident that planted the seeds for his completely rational anxiety:
“My house was robbed a few years ago — and I saw the guy come in. I was watching ‘The Irishman’ and I could see, through the bedroom door, this guy in my living room, on all fours, looking for things. In the end, he just took some Kit Kats. That’s all he got. He was also wearing my coat, which was a strange experience. It kind of stays with you, almost like PTSD. It really froze me. You don’t know if he’s got a weapon or what his intentions are. The movie kind of triggers that slightly.”
The would-be burglar didn’t break in with the blunt and bladed weapons that Redmond and his crew use in “Knock at the Cabin,” either. Grint mentioned that he “waltzed in fairly effortlessly,” and most likely didn’t even know about the homeowner’s famous identity. Perhaps acting in Shyamalan’s film allowed Grint to therapeutically mirror that harrowing situation, though his character’s intentions are much more sinister than searching for Kit Kats.