They've gotten me once. I was prepared this time.

[Crowley finally finds a steady pace with long strides that keep him in sync with her running.]

Exploring and looking for someone. Caught your scent and thought I couldn't leave you out here alone. You humans are prone to trouble. Believe me, I would know.

[He might've been looking for his angel. He found the Doctor's angel instead.]

You two--You and the doctor, you travel the universe together? You were rambling a bit in your sleep.