Hi Devo,
The first time I saw a nurse shark, I alsmost swallowed my regulator. After years of going there, I found out that they don't bite even if you pull their tail!
Our dive instructor, we just finished Rescue Diver last year, is Sylvin Forman at Bottom Time (bottomtime@btl.net. He's just wonderful. If he's not training someone, he can take you out. If not, the other guys are great, too. Sylvin and his brother Allan were two of the first divers on Ambergris, so you'll get great knowledge and experience. Tell him Marie and John send our love! Marie Rallis