Back story: I live alone in a 2-story townhouse with my master bedroom located upstairs. I am torn between locking my door or keeping it wide open. On one side, locking the door could potentially create an additional barrier if a bad guy were to break in; this could give me the time I need to grab my gun and jump behind my bed. The only negative I see in this scenario is that the closed door greatly prohibits my auditory awareness of what's going on downstairs. With the door open I can actually hear a lot going on since my bedroom is located right at the top of the stairs. Opinions?