At the beginning of the episode, the building where the woman goes to see the healer is the same one where the website owner lived and was confronted by Olivia in the previous episode. You can tell from the entry with stairs and the red light next to the door.
Ayahuasca is a South American psychoactive and entheogenic brewed drink traditionally used both socially and as a ceremonial or shamanic spiritual medicine among the indigenous peoples of the Amazon basin, and more recently in North America and Europe. The tea causes altered states of consciousness often known as "psychedelic experiences" which include visual hallucinations and altered perceptions of reality.