Is the theme of this series atonement? The Doctor has a second chance at life after receiving more regenerations from the Time Lords on Gallifrey. Its interesting that the Doctor has cycled back to the beginning of his travels. Once again hes about to leave Coal Hill School with two teachers. Even his grumpy exterior is reminiscent of the first Doctors persona. Is the Doctor trying to take this journey again but see it with more adult eyes? Is he trying to find a way to amend past mistakes? Danny is haunted by past actions. Yet he has evolved from soldier to teacher. Perhaps he too is endeavoring to grow up and into a more nuanced life. Theres a reason why the young are conscripted. Its much easier to fill inexperienced hearts and minds with righteous fervor.