If the player looks around at the start of the mission, they will usually find that Sergeant Moody is in command of one or two lieutenants.
Sgt. Moody instructs third squad to provide covering fire with the Browning M1919, but no one is carrying a Browning M1919. There are .30 cal game files and models, so that dialogue was recorded before the decision of not including the .30 cal.
It's possible not to give Sgt. Moody enough covering fire while he is carrying the wounded soldier causing him to be shot and injured, but Moody will stay behind regardless of how much covering fire is actually given.