The Empath is one of my favorite TOS episodes. After Kirk volunteers (in the scene above) to be tortured in the place of Spock and Bones, the Vians tell him, “We’ve already observed the intensity of your passions, engaged your capacity to love others.” Later in the episode, Spock volunteers to be tortured in place of Bones, and Bones knocks him out with a hypo to prevent it. The crux of the episode hinges on the Triumvirate’s ability to sacrifice for one another, to love each other more than they fear pain and suffering. It’s a goddamn beautiful episode. 

In summary, it’s this comic in Star Trek form: