Who is Doc from The Killing Zone: My Life in the Vietnam War and what is their importance?

Doc is the generic name for a platoon's medical officer. Lt. Downs has difficulty with his medical officer (Medic) in the jungle. The Medic, or Doc is described as an overweight boy, aged 18 from Texas, who thinks he has no other duties than patching up men if they are wounded. Doc is given a talk by the battalion Surgeon Officer about his duties as a soldier and in combat. After this, the problem appears to be resolved.