Leaving the spiders to make bigger holes isn't true. Probably they'll just kill you so it's the best to kill them before they kill you. Also when you're already inside the spider cave, you must have a revive potion because the spiders will probably kill you then you will be warped at the nearest hospital. Also you need a stronger melee or gun if possible because the spider queen escapes quickly. (I don't know about the webs.. Anyone knows what it does?)