Who’s been murdering newlyweds, turning a beachy paradise into a tropical hell shared by three pretty couples? You’ll probably guess, but that doesn’t take away from the slicked-up genre charms of A Perfect Getaway, a summery suspense thriller from writer-director David Twohy (Pitch Black). Steve Zahn makes full use of the many varieties of hyper in his acting arsenal, while Timothy Olyphant has a heckuva good time telegraphing macho mania. The picture treats itself to all sorts of artsy camera tricks. And no, you’re not tripping: The movie is set in Hawaii but was shot in…Puerto Rico. B?