[@Shurikai]

The Warrior Code and the Medicine Cat Code haven't been formed as of yet since two of the five clans only recently came together. In Cliff and Ash, Medicine Cats are taught more then just medicine. They're allowed mates after they've finished a certain term. In Light, a Medicine Cat is a healer as well as a Warrior, and when they prove themselves they may claim/be claimed, as the mate of choice.