OOBE in crowded place????

[Usiimers]

Hello friends
I'm new to this forum.  Some of you might know me from the Astral Society though.  Anyway, I had a strange experience yesterday.  
I was studying in the library at my college with a friend.  I started wondering if it was possible to go OOB in a crowded place.  I was feeling tired and relaxed and decided to give it a try.  
The confusing thing, is that it worked only for, what felt like maybe 30 seconds.
I heard strange murmuring of people turn into strange, otherworldly sounds.  Then I started vibrating and ended up seeing outside.  I was only slightly above my body.  
I swung my hands in front of my face.  At first I saw nothing, then I saw what seemed like see through-like hands that were very fluid.  I then read a sign that was up and had clear letters.  I later verified this when I awoke!  I hadn't read it before the OBE.  
ALso, my friend was next to me studying and I tried to yell at her and grab in her direction, but she didn't notice.  I had trouble moving around and eventually the noise must have snapped me back into my body, and back into conciousness.  
This was an extremely interesting and bizarre experience.  Has anyone else had anything like this?  
I didn't know it was possible to do this in a crowded place.  This experience also gave me a verifiable thing, which was the sign with big block letters which I examined in this state.  
Any feedback would be helpful!
-Usiim