When the "Good Dale" goes out of the Lodge in Part 2, he is pulled into the Glass Box in New York. Then, Cooper goes to the Purple Room where he meets Naido. I place all this events at the same time as Ruth Davenport murder, on Thursday, September 22, 2016.
According to my study on chronology (which is, of course, theorical), and according to Bill Hastings interrogation, Ruth murder happens on a thursday. In his second interrogation, Bill Hastings says he had visions of Garland Briggs floating head saying "Cooper, Cooper", in his visions during the murder.
In New York, Cooper is floating. In his scene with Naido, he sees Garland Briggs floating head into the space. Naido also makes movements with her arm, indicating a decapitation to Cooper.
Then, after Naido sacrifices herself, Cooper arrives in another room whith a "3" machine. When he takes place of Dougie Jones, we are on Sunday, September 25, 2016 (according to my theorical chronology once again) : so Naido and the American Girl send Cooper 3 days later.
The death of Sam and Tracey in New York, the apparition of the "Experiment" (Judy?), of Cooper in the box, and the scenes with Cooper in the Purple Room may all happen at the same time, during Ruth Davenport murder on September 22.