Yes, you should leave a spider in your room, because it does not care about you and does not want to have anything to do with you, so it won’t hurt you at all. Most people have spiders in their home without knowing it because they are just bugs, and they stay out of your way most of the time. However, if you are so scared of the spider in your home that you can’t seem to focus on anything, try to capture it or get someone else to do it, and leave it outside, instead of finish it off for no reason.