Richard, knowing when to use the gun is of paramount importance. For instance, you NEVER shoot at a fleeing felon.
Also, if you and your buddy had kicked the door in and pointed weapons at the rapist, he would be a fool to resist. (Unless he could sense that you were scared shitless)
Part of being an effective officer is the ability to convince the perp that he is in mortal danger by messing with you. It's called "officer presence". Barney Fife, on the old Andy Griffith show was a good example of an ineffective cop. He was a joke.