An army with the Disruption Force Disposition facing one with Purge the Foe is dealt Delaying Action as its primary mission.
The opposing army is not playing the same mission: it is dealt Punishment. Reading only your own card is how a game gets lost from in front.
Disruption against Purge-the-Foe. Every enemy unit destroyed pays at the end of your turn. From the second battle round, non-home control pays at the end of your Command phase, and holding at least one central objective together with at least one expansion objective pays again at end of turn.
Primary scoring is capped at 15 victory points in a battle round and 45 across the game.