I'm sorry, do we meet Dana specifically in the books? I remember that they met Darkfriends along the way, but I couldn't remember that specific instance...
I am a bit miffed though, that we saw some of how Nynaeve got away, but how did she get across the River? And why did she leave her Village that she is responsible for? That part was better explained in the book, though maybe we will get that when Nynaeve and Egwene meet again...