Wow sounds scary. to be honest you are brave going it alone anyway and for playing that game. I wish I could, so your doing good just for that . I NEVER go downstairs at night alone. Sometimes when I used to play games (bit rubbish at them now, lost my skill) I used to hear the sounds from it for some time after I stopped playing. Like all of a sudden the noise would happen and then switch off. Maybe its the same, idk, could be really could not be, only you know, I dont really know, just giving you some idea what it could be.