You can pretty much thank Teyla for teaching John how to fight and Ronan for the training. John was the only military man that didnt seem to have any hand to hand combat training until Teyla came along. Even Lt. Ford (he was a Marine) had efficient hand to hand combat skills.
cont- Sheppard learned the worst way that to keep his people safe he needs to make sacrifices. Michael gets his vengeance, but for how long? ( I need find time to write this fic..)