A 'Mile', like a "way", signifies a progression in states of understanding or of love. It can be a progression in a good direction, or in a bad one.

Apocalypse Explained 556:9, in discussing the famous "going the extra mile" verse in Matthew 5:41, mentions its similarity to the concept "way", and "way" is treated of in Arcana Coelestia 2287, 2331, 2333, 3142, and elsewhere.