During that initial airing in 1966, I wonder how many viewers thought the creature might have successfully killed Uhura? I'm sure we're all glad that did not happen, but you have to admit the "set up" was almost "classic". We get that hint of character development near the beginning of the episode, first her gentle "teasing" and then her chastising Spock's seeming indifference, (hopefully) making us care for the Lieutenant. Thus when the creature did drain and kill her, its actions would seem all the more horrific.
On a related note, her chastising observation is the kind of material that later would have been given to McCoy, but since he was the focus of the story and upon the planet with Kirk.
On a related note, her chastising observation is the kind of material that later would have been given to McCoy, but since he was the focus of the story and upon the planet with Kirk.