I cant belive the fear I see here, someone knocks on the door and panic ensues?
This isnt about a person simply knocking at the door. Its about how your instincts warn you of something that is amiss. What we sense is not always so easy to put into words when it about feeling or visual perception. I think that this post boils down to the fact that the fellow who was at the door, behaved oddly under the circumstances. We dont live in 1950's Mayberry anymore and when someone who knocks at the door does not act normal.. its certainly a possibility that bad thing are afoot.
In my town there is a alley that runs between a pizza place and a movie theater... As a teen in the late 70's I would always cut through the alley when going over to the movie theater. One night as I walked about 15 feet into the alley, i stopped. Something didnt feel right and it wasnt anything that I could put my finger on. Purhaps it was an absense of something, absense of sound maybe. It seemed oddly quiet but I wasnt sure it was even that at all, just a feeling. I had a am/fm radio to my head and couldnt really hear anyway but I stood there a few seconds more then turned and walked the long way aound. Later that night ( in the alley) a guy was robbed of his wallet and jacket by a unknown male that was never found. A rather dim light that was normally on all night- above the rear door of the pizza place was broken and thats where the robbery occured. I think the added darkenss was what I picked up on but it didnt really register due to it being such a subtle difference. I could have just shrugged my shoulders and walked down the alley but I didnt. I followed my gut instinct about the situation and didnt try to convince myself otherwise.
The moral of this story is that when and if your gut tells you something is wrong... its very likely it is.