It's an animal...they are all unpredictable and you WILL get bitten over time if you own snakes. Judging by the way you described her "hanging on" it sounds like she may have been hungry? If it is in defense, they will strick and let gow. I have also never heard of one biting so they wouldn't fall.

A similar thing happend to me at a show this weekend. I held a blue eyed lucy that a breeder i regularly buy from produced...out of nowhere she tagged me. it's to be expected.