RO is a very realistic game, but I always missed the kind of doctor.
My idea of how this class could be adapted to the game is as follows.
When you kill a soldier, except for a clear shot in the head (it is impossible to cure a man shot in the head), but this fall, will fall as low, but do not have to be dead. To drop the player will be reborn as has always happened, but the character may be rescued by a doctor with the aim of increasing the percentage of reinforcement. By this I mean that the player dies after falling as if it were low, but the osldado stay on the battlefield, not as dead as a low but unable to fight, that is the time where the physician can make a bandage and rescue in order to increase the percentage of reinforcement.
Depending on where the impact affects the soldier, they will be more or less time to survive.
Other functions of the physician can be wear bandages and heal injuries but trained soldiers in combat, but only in case of minor injuries such as arms and legs. A soldier if he is shot in the abdomen can not keep fighting.