Leandro the Lion Man and Sam Swift are so superfluous to the script they are hard to recall. They serve no purpose whatsoever other than to get in the way of the main plot line. Ashildrs journey is the story here and deviations from it feel shoe-horned in. Its interesting that while each episode of this two-parter was written by a different person their flaws are quite similar. Perhaps Ashildrs tale was so compelling it was difficult to find an antagonist to compete with it. Its brave and right that Catherine Treganna chooses to leave the relationship between the Doctor and Ashildr open to interpretation. They are neither friends nor enemies and yet they are also both of these things. The chemistry between them is akin to what the Doctor shares with the Master if only that person were not quite so insane. They are aware of each others power and failings and they are both watching. Ashildr may be slated to return in a later episode and the chance to see where this riveting characters story goes would definitely be welcome.