Severance season two finale explained: What is Cold Harbor?

What is Cold Harbor? Meanwhile, Gemma has entered the Cold Harbor room on the Testing Floor where she is observed on monitors by both Jame Eagan and Dr Mauer in seperate rooms.

Throughout the season viewers have been led to believe that Gemma will die once Cold Harbor has been completed, which is confirmed here by Cobel.

Outie Mark obliges and the very next scene is Mark arriving on the severed floor, closely followed by Helly.