So as I was running through the beta on my Wizard earlier today and I found this strange NPC called "Lloigor the Crazed" whom I had never encountered before. After speaking with him and then "stealing" a tome, he started to attack me. Needless to say, it was pretty damn cool.
Providing a few screenshots of the whole thing: http://imgur.com/a/O4ab2/#0.
Has anyone else found some rare events or NPCs in the beta? Please share your stories and screenshots!
So I'll just close this duplicate.