St. Bernards are notorious for being a badass breed of dog. They're considered to be working dogs, originally bred to rescue people from avalanches. They're also massive and can weigh nearly 300 pounds. Safe to say they can handle their business.
However, they're still dogs, and therefore lack common sense. Take for instance this massive pooch. He could dig you out of a snow tomb, but he's afraid to walk down the steps from the attic. He's so terrified that his owner has to do some heavy lifting to get him downstairs!