There is a lot of symbolism in this movie, apparently. (I've been told this, and don't know myself.) BUT there are so many problems with the portrayal of the events and the set up from a story-telling stand point, as well as the ending, which is so obvious and yet the characters are so oblivious to it. Plus not only is there no resolution, but the main character totally get's shafted and in NO way would come out of this as sane as she does.
Well, let's just say it's not meant to be a satisfying movie, but a thought-provoking one. Personally, I don't feel that there's a lot of value in the thoughts that it provokes. If you understand it, it's pointless, and if you don't understand it, you'll probably never care to really try.