Warehouse Worker

The Warehouse Workers are the two people encountered on the mission

Citadel: Expose Saren right before you fight Fist. When Shepard confront the warehouse workers, he can use Charm or Intimidate to avoid the fight. The alternative to persuasion is a firefight.

Tactics
Warehouse Workers are among the weakest enemies in the entire game. They lack the shields that the Bartender and Thug have and only wield pistols. Any method of attack can kill these two almost instantly.