Going up and down stairs is a regular part of most people’s days. Whether you live in a two-story house, work on the fifth floor of an office building, or live in a city with lots of hills and stairs to climb, you probably don’t think much about them when you encounter a flight of stairs. But I’m sure we all know that feeling where you accidentally misstep while walking down them or think you’ve reached a last step a tad bit prematurely, and suddenly, your heart skips a beat and your life flashes before your eyes. Going up or down a staircase can be the most mundane activity in your day, or it can be the most frightening moment in an otherwise normal and safe day…