I noticed a little something in ``Plato's Stepchildren''. In the big humiliation scene that ends with Alexander riding Kirk ... McCoy does at one point beg Parmen to stop it. But he isn't moved to beg by any of the danger or humiliation inflicted on Kirk. He begs it when the Platonians force Spock to laugh and then to cry. I'm not sure if it's just that at that moment McCoy has had enough, or if it's that he's aware being forced to show emotions -- even ones he doesn't feel or has controlled himself -- is vastly harder for Spock than just surviving this scene is for Kirk, and wanting to save Spock because he needs the saving more.