The Eternals don't have human ingenuity and imagination of their own, something that Ephemerals, or as Tegan says accurately, "human beings," are gifted with. The Doctor denounces them as parasites who feed on living minds.
Turlough's desperation is at a fever pitch here. He constantly beseeches the Black Guardian for advice, but by this time, the powerful being is fed up with the boy and has doomed him to living until he kills the Doctor. He looks more to the Doctor as his source of guidance and protection, but the weasel always working to better his position, especially when it appears he is joining sides with Wrack, the menacing pirate captain of the Buccaneer who has an equally menacing laugh. Kudos to Lynda Barron.
Tegan's her usual grumpy self, but she does show outrage when the Eternals react to the destruction of a rival competitor without compassion. Heck, I would be grumpy if I was being courted by a first mate who finds my mind fascinating.
In the dinner scene, the Doctor appreciates fine wine like he did in Day Of The Daleks. He also finds time to change his celery.
The best line is when the Doctor tells the seasick Tegan, "Brave heart, Tegan." To which the hapless Australian replies, "It's not my heart I'm worried about."
Marriner is the only Eternal who is the closest to likable, as he helps the Doctor aboard the Buccaneer. True, his obsession with Tegan makes him like a creep sometimes, but he is beginning to find out what it's like to be human. If he could choose, would he forsake his immortality in exchange for living with Tegan, or is his emotional insulation, as Romana would've called it, too advanced for him to actually care for her? It's almost like Wim Wenders' Himmel Uber Berlin.
The balance of power in the universe can be summed up in this exchange between the Black and White Guardian.
White Guardian: You will never destroy the light.Black Guardian: Others will do it for me.White Guardian: Destroy the light and you destroy yourself. Dark cannot exist without knowledge of light.Black Guardian: "Nor light without dark."
That knowledge itself is enlightening.
