Or, as some have speculated, if something else happened with Miriam when she went down the wrong staircase in the library and this isn't her acting of her own free will.
I read the vision of Judith on the staircase as some kind of message to Miriam that she would understand. I didn't see it as something that would trigger a change in her behaviour so much as a sign that someone knows what she is and what she's doing (with that someone possibly just being Miriam herself).
I've long suggested that Miriam might be the "Anti-Adrian". I figure their respective parentage is a little uncertain now. (I really don't know what we're supposed to take away from the eighties flashback but Miriam appears to have Patrick's magic touch, whereas Adrian doesn't seem to. But then what was the significance of Jakob having had sex with both Miel and Jacqui long before - it would seem - Adrian and Miriam were conceived? And Patrick appears to have had a sexual relationship with - it would seem - Erin's mother, so might Miriam and Erin be half-sisters?) But Miriam and Adrian are very close to being the same age, with Miriam having been very much the focus of Jakob's interest (and might that have started even before her conception?).
So I'm still seeing Miriam's ultimate adversary as being Adrian, with Erin simply being Adrian's closest and possibly most powerful protector. But obviously that could be a totally wrong reading.
This is Erin's bedroom rather than Dani's, but this scene is reminding me of Dani and Erin using the pendant on Miriam a matter of days ago.