I think it's about the indecision in "Marisol's" head. I think she has finally realized what she wants to do with her life and is going to realize her dream. I also agree with Lyricsarepoetry that it's about letting go and moving on- I think "Marisol" is leaving her current life (family and friends) behind. And as Lyricsarepoetry said "getting on a train" and getting away. When Emily says "And she's searching through the faces of the crowded streets, she doesn't know a single soul, but she feels so free" it shows that she doesn't mind leaving everything behind. :)