Authors love to give their characters the illusion of free will; it makes their job easier, not having to micromanage the characters, or consequently be the only protagonist. This illusion can be supported by sometimes letting the characters have their way, or letting them think that the author did not foresee an event in his own comic. They're one in the same.
Also, CHASING after someone? How pedestrian. Your the author! Chasing is for non-pan dimensional, extraplaner beings.