Kill the Moon. Well that was certainly quite multi-layered. Throughout this series we have seen more of the darker side of the Doctor. After the light-heartedness of last week we get a quite different story. It feels more adult, with the language and the morally complex story. It is realistic that humanity would choose their survival. The Doctor's actions lead to more strain, with him leaving the humans behind and as usual Capaldi gives a great performance. Spiders decent monster. Courtney puts aside the arrogant nature of last week and we see more character, as she is scared and debating on killing the creature. But scientific oddities, like the idea of the moon being an egg. That is literally a Super Friends plot. And the hatching creature laying another egg seemed a slight cop out. But ending was good. Finally we see Clara realise more the difficulties of travel with the Doctor. And she leaves TARDIS by own will, something that hasn't happened to a main companion for seven years.