The Doctor told Ashildr that he hadn't arrived in 16th Century England looking to take her away; it was just a coincidence that they happened to be looking for the same amulet. But what if that wasn't the complete truth? The Doctor told her the last time he saw her was when she was running a leper colony; her compassion obviously had some lasting effect for her to take up the care of the terminally ill. While she never saw him, this suggested that the Doctor had checked in on her at least once since the incident with the Mire. Had he been watching her for a while? And now he has seen what she has become 800 years after her 'resurrection' will this become a regular gig?