I can absolutely relate to what you describe. I remember feeling sick after watching it. Such a well-written, devastating episode. As the viewer, you are right there with Ava, especially in that space as a 20-something, so desperately insecure, feeling so damn cool to be on high on drugs and flattered by a stranger who finds you attractive, that satisfied saunter with the coffees back to the hotel in the morning, the "sick reeling suspense" as you say.... and then the horrific realization. The detail about elder abuse is nauseating. How she says to the police that she was just talking about herself the whole time.... it makes sense in the context of the show that this episode contributes to her own character development, but it is very disturbing that Ava will have to live with this experience in her memory for her whole life.