A badly wounded batarian may actually be a terrorist. Find him in the refugee camp and investigate.
In the Citadel's Docks: Holding Area, go to the back of Cargo Hold C. There will be a turian nurse standing outside a refugee accommodation. Talk to the nurse, who tells you about the wounded terrorist's chances of survival, after which you will be allowed to talk to his batarian patient.
Ghorek will admit to wanting to avenge his homeworld, Aratoht, the colony destroyed in the Alpha Relay explosion. His motivation is the same, regardless of whether or not the Commander personally took part in these events. If Shepard was there, the exchange will be a bit more personal on both sides. Either way, Ghorek asks Shepard for mercy, and to take him off life support. You can either fulfill his request, or let the nurse administer a sedative. If the option to disable the life support is taken, Ghorek will thank Shepard before dying.
Taking Ghorek off life support does not elicit a reaction from the nurse. After completing this mission, you will be granted 5 Reputation, 210 experience and 5,000 credits.