Getting "surprised" by first auditory hypnagogic imagery

I'll be honest, I took the unrecommended attempt of WILDING at sleep time.
However I managed to stay awake, and while not moving, I guess I could feel my dream personality in my head as I felt that I was doing something although I wasn't doing anything with my physical body.
Anyway, after a while, I had my first hypnagogic imagery ever (I never succeeded at WILDing): I heard a vibration similar to binaural beats (I wasn't using any binaural beat). It didn't literally scare me, but the surprise caused my heart to jump and seemed to cancel everything.
What to do next time? Where did I go wrong?

Well what you did wrong was get too excited. Next time just stay calm through the whole thing I would assume ( I've never actually done WILD yet )

Its ok, it happens. Next time you will be more prepared for the auditory hallucinations. Just try to keep calm, and if you do jump a bit, try and recover (back to calmness) quickly. I remember the first time I heard metal shredding in one of these. Knocked me clean out of SP. Sometimes that "heart jump feeling" is also a hallucination, so don't give up if it happens. You may indeed still be transitioning. Good luck in your next attempt!