I know what you mean. I have awakened and it seemed like I could hear someone saying something out loud almost yelling but once i wake up it stops. Some time ago I kept waking up to the sound of a child calling her mother, but of course i thought i was dreaming, later on I asked my mom if she had heard anything and she said she heard little girl crying. I dont know why these things happen but I pray on them immediatly just in case someone is trying to reach out for help. Maybe were all kind of pyshic and so we pick up on things, but yes I would get rid of the ventilator too.