Making a combat medic, as part of the life modules picked Military academy - medicine and tour of duty - medicine.

Academy gives Academic Knowledge: Medicine +6
TOD gives Professional Knowledge: Medicine +3

I could see medicine being either one, but not both.

The practice of medicine is actually covered by the Medicine Active Skill. A combat medic would actually be more versed in the use of the First Aid Active Skill.

Medicine is also an academic field, and thus can be considered as an Academic Knowledge Skill. It is actually a very broad field, which encompasses anatomy, genetics, neuroscience, microbiology, nutrition and many other things, but applied to (meta)humans only. The thing is, the point of medical praticians training is to teach them the exact set of academic knowledge they need to be effective. Medicine is (only) Applied Biology. An excellent surgeon may otherwise be a mediocre biologist.

The difference between Academic Knowledge Skills and Active Skills is the ability to deal with real situations. It is one thing to remember every airborne virus with natural reservoirs in North America (from the virology subfield of medicine) and the available treatments for their symptoms (from the pharmacology subfield). It is another to program medical analysis in the right order to quickly establish a proper diagnosis and deliver treatment, all the while taking into account the patient specific metabolism. That's the gap between a knowledge and an active skill. The knowledge skill allow to understand what is going on, but should not allow to set a course of action.

The Professional Knowledge Skills are where the divide between Active skills and the different types of Knowledge Skills is the less obvious. A number of them covers topics for which no Active Skill is available (Architecture, Engineering...) but since there are officially Knowledge Skills, people consider they should include some Academic knowledge (like knowledge of Physics with the Engineering Skill for example) or Street knowledge as well (like knowledge of army units with the Military skill).

If the definitions were to be strictly enforced, a Medicine Professional Knowledge skill would actually cover how to run a cabinet, a clinic or a Medical Battalion, properly place order for drugs and surgery instruments and store them, wash your hands before a surgical act, fill insurance paperwork, etc.

Yes, it was just what to me looked like an inconsistent skill listing in the system. Oh well.

It seems to me that Medicine could absolutely be both. Understanding Medicine as a Professional Knowledge skill would encompass applications of community health and the pros and cons of an internal medicine paradigm. Medicine as an Academic Knowledge skill would include the history of medicine, medical educational theory - maybe some insight into how medicine is taught and practiced in other areas than your own. There would be a ton of overlap between the two, but I could see them being different skills.

Game application differences should be minimal. It's all about the character flavor.