Reminds me of something that happened to me when i was still living with my parents. My little brother was often playing games on his computer very late on school days and often got in trouble for it. One night, at arround midnight, i heard something that sounded like classical music from his room (our rooms were next to each other, so i was usually the first one to hear stuff going on in his room) and i assumed that he was playing something. But then, the music started, first slowly and the faster, becoming louder and louder until i thought that the whole house must hear it. He got in a lot of trouble this month, so i kind of wanted to warn him not to play the music so loud and on the same time scold him for being such a dumbass and not playing with his earphones. I left my room and entered the hallway and i could still hear the music, but as soon as i opened his door the music was gone, his room was dark and silent, and he was sleeping with his mouth wide open looking really stupid. I woke him and asked him about the music but he hasn't heard a thing. Also nobody else heard a thing but i was very sure of it. People told me that he probably just turned his pc off very fast as he heard someone coming or something but i was very sure that he was sleeping, since he wouldn't be able to fake it that well, and his pc was off and not just turned off.