The Descent: very scary. Making the horror movie: scarier. Before she played the leader of an ill-fated cave-diving expedition, Mendoza braved a real cave to get a feel for what it's like down there. "The guides forced me to lead the group," says the Aussie actress, 28. "It was absolutely terrifying. You are really on survival instincts." By the end of filming, "I realized I'm not as delicate as I thought I was."