It is actually insane to me that the story kind of brushes past the (very understandable) intense concern Six has upon realizing Mel was drugged out of her mind, helpless, and essentially trapped in a household with a possessive, intensely not okay man for actual months. Sure, Mel doesn't have any memory of anything that might have happened, but it's still horrific to think about.

It's such an insanely terrifying implication to tuck inside of an otherwise pretty average Doctor Who story.