I heard that when doing WILD you may hear sounds such as screeching or somthing, but the other morning I woke up and was still half asleep, I was not trying to WILD or induce a lucid dream in anyway and I could what sounded like someone Bashing on a metal door, after that went on for what seemed like a minute or two I got out of bed and asked my mum what the banging was, she didn't have a clue what I was talking about. Would that be Hypnagogic Sound?