You were exploring the mansion of a rich individual, you were not permitted to be there nor did you ask for permission, you just welcomed yourself into this person's house (Wow.) You had tried to open the house door to begin exploring this place and the door swung open, with little to no resistance. (Strange.) You then turned around to a sort of electrical buzzing zoom past your eyes and ears. You felt you weren't here alone. But that should've been obvious.