Whatever frightened you, whatever you thought might happen someday, is not happening now. This is only a test so we can be sure we can tell you when we think it’s happening before it does or at last no later than simultaneously. What you should do (when you hear the official sound we’re about to make at almost any moment) is to listen as closely as you can, then tell yourself This is what it’s going to sound like When it might happen. You’ll remember how to hear yourself thinking if it ever does.