Janey E said that line
Cooper/Dougie came out of his coma quickly after all but I think that line sets it up that Audrey is still in he coma and all her scenes this season have been in her own mind.
People speculated that Audrey might be in a coma this whole time. But when she woke up/came to her senses, she was looking in the mirror. I don't think that many coma patients have a habit of looking in the mirror.
My theory is that Audrey was in the similar state of mind as Dougie. Right before Dougie turned into Cooper, we could hear that sound we already heard before in the Great Northern Hotel. The sound might be a precursor to a person coming back to his/her senses. If Audrey is kept in some room in a Great Norther Hotel, the sound we heard in the hotel might mean the same thing for her as the sound in a hospital meant for Cooper.
So do you think Audrey is a tulpa?
Dougie never turned into Cooper. Dougie was a tulpa, he went into the lodge and Cooper came out of the lodge and took Dougie's place, but it was not one thing turning into the other. They each had their own body and mind. Dougie's mind stayed in Dougie's body, which got turned into the gold seed.
The same thing that happened to Diane.