So Will thinks bad people are out to get him, so he gets a gun. If the bad people visit him what good is the gun if he is not carrying it at the time, certainly no good if it is in the shed or behind the garage. So he hides it in the car but does not lock it, Harriet takes it, but needs Cain to get rid of it, instead of just throwing it in the quarry. This is just a contrived tale which might involve Cain either using it getting caught with it, or will someone else get hold of it and some tragedy occur?