On some level I like this idea. My concern is that if it was setup as described, to train people would just stand deep enough in water or stand in one of the cold zones and let their health run down low and just use kits to stay alive till they reached the level of First Aid they wanted. If it was combat only, then it seems it could work. But it makes leveling First Aid and Armor Patching more difficult to do and more complex to understand. A bonus xp value labeled as such, if you save yourself in battle from the brink of death might achieve some of what you are trying for. Also I can see people getting angry in certain cases, for example a player uses first aid on the tank person during a Manitcore run but get nearly no XP even though the tank was down to near 0 health, but others in the group saw the tank needed help and applied various healing abilities, and are awarded the right % of xp for the amount they healed. But it be difficult to tell who did the healing, and a player might assume they didn't get what they should get. So it is a timing issue. Or someone tries to help you out in a fight by healing you and messes up your XP because you are at full health when you apply first aid, wasted kit.