Be sure to engage both mobs when they spawn. Do not pull one away from the other, as they will despawn and you will fail the mission.
The NMs have a rage timer at around 10-20 minutes. They then behave as a raged mob would if the mob is not killed within the time limit; resisting spells and dealing far greater amounts of damage. ----
Others assisting with the fight may also check the ??? after the win for an exp/limit reward regardless of whether they have the mission active. However. if they do not have the mission active, they will not receive Allied Notes or credit for the victory.