I love this Music Video. Its almost like a female version of SHINee's View.
What me and my friends see in this Mv, our interpretation, is: the broken cup is Sulli leaving which had an affects on all the members, as we see by luna’s feet getting cut. The members running through the forest could mean that they feel lost or that they are looking for Sulli (or even both). In the end, Victoria stops the cup from breaking, meaning that (not only) through her leadership f(x) will move on and support each other.
What are your thoughts of the Music Video?