We're All Dying (The Immunity Syndrome)

KIRK: This is the Captain. We're on a difficult mission, but it's not the first time. Our orders do not say stay alive or retreat. 
[Engineering] 
KIRK [OC]: Our mission is to investigate. 
[Sickbay] 
KIRK [OC]: We're sick, and we're getting sicker. 
[Bridge] 
KIRK: We have no guarantees, but we have a good ship and the best crew in Starfleet. So do your jobs. Carry on. Kirk out. 
[McCoy's office] 
MCCOY: Sickbay to Captain Kirk. 
KIRK [OC]: Kirk here. Go ahead, Bones. 
MCCOY: Jim, according to the life indicators, the energy levels 
[Bridge] 
KIRK: Yes, say it, Bones. 
[McCoy's office] 
MCCOY: According to the life monitors, we're dying. 
[Bridge] 
MCCOY [OC]: We're all dying.