Two very different books — two very different songs.
The song Breathless by the Corrs is about the exhilaration of hurtling towards romance, kind of like the plot in Breathe. On the other hand, Breathe by Anna Nalick is a haunting song of pain that must be endured.
The songs, then, are switched to match the mood of the books with corresponding titles. Listen to see if you would agree!