At one point it seemed like a loud high-pitched siren went off in my ears. Very unnerving! Then once when I was getting flashes of imagery one image began to shake. Does that sometimes happen with the onset of vibrations? Anyway, I was feeling rather nervous at that point because it sounded and felt as if someone was standing next to me. I felt as if I kept hitting the right level of trance only briefly over and over. I just couldn't maintain it. I never had any physical sensations.