The huge shock was the death of Chloe and Max's inability to rewind time and stop it.
As we see in the disturbing post-credits tease, Jefferson has access to the dark room as well – confirming the connection, but how have the pair been operating? The assumption will be that Jefferson is the driving force, taking advantage of Nathan's issues and wealth. Prescott is guilty of plenty, but it appears Jefferson has been working alongside him as part of a sick and twisted 'working partnership'. One of the numerous beached whales in one of episode four\'s opening shots.
