To run a mile means to avoid something in any way possible, and in this context she wants to avoid him by fleeing the scene.
Consider the staetement "There was something about Callum's behaviour that she didn't like, something in his grin that made her want to flee the scene immediately.". Based on this statement, is "There was something about callums behaviour that she didn't like, something in his grin that made her want to run a mile." a true statement? Yes/no/unknown