Flynn is shown in flashbacks receiving news from an Army officer that the Secretary of the Army regrets to inform him of the death of his son. Flynn is later seen holding his son's dog tags which say "Marines". A USMC or U.S. naval officer would have notified the Flynns had their son been a Marine.
Towards the end of the episode, as the weapon is launched, the Marine Sergeant Major behind Flynn carries an officer's cover (hat), distinguished by the quatrefoil on the top.
Danny's grave was perfectly rectangular, revealing it had been dug by a machine, not the shovels the rebels had on hand.
When the Monroe people are sealing the exits, a character points his rifle at a door. A gun cocking sound is heard but the character did not cock the gun.