In the actual season, however, I don't recall that scene ever taking place. Moreover, I don't see any place in the chronology where that would really fit into the story either. It resembles episode 9 a little bit, where Noora wakes up at Niko's place. However, in that episode, William wasn't there, yet William shows up in the trailer.
So, I'm not sure if the trailer fits into the chronology at all. So, what is the deal with the trailer? I remember reading about the creator of the series saying that she used to change the story as she went. Maybe the event from the trailer was originally intended to be a part of the story, but then it was changed?