In her new film, Jodie Foster, 39, plays a divorced mom who moves into a New York apartment equipped with a reinforced shelter designed to protect its occupants during emergencies. In her real life, the star of “Panic Room” believes such extreme measures are futile. “I suppose I should be more concerned, but that’s just not the way I want to be,” the mother of Charles, 3, and Kit, 3 months, explains in an interview with USA Today. Despite Foster’s own brush with a deranged fan — would-be assassin John Hinckley cited her as the reason he shot then-President Ronald Reagan in 1981 — she says she refuses to live her life in fear. “I was reading a book recently by (Hollywood security expert) Gavin de Becker, in which he says that if people really want to kill you, they will,” Foster tells USA Today. “There’s no real safe place to hide, so you’re better off just keeping your eyes diligently open at all times.” Foster also played it cool when she found herself confined for hours with “Panic Room” costar Kristen Stewart, 11, during filming. “We basically spent five months together in a box,” she tells the newspaper. “Kristen and I would just hang out. Talk about school. Talk about boys. Talk about bands we like, like U2. Anything to give you a break from the intense emotion you were summoning.” “Panic Room” opens Friday.