During Christmas2016, Moira told Bill she had found pictures of Bill's mum on the back of the cupboard, and that she wasn't even aware they had these photos.
Later, Bill returned to her flat to hear the shower running. When she received a call from Moira, she was surprised to hear no one was staying over. Upon investigating further, she found out that the sentient oil had followed her to her flat. (TV: The Pilot)