Good point!
OK, so what we know is that about 1 minute or so before the plane started to descend there was communication with the ATC. I would assume both pilots are in the cockpit then, one pilot leaves and then the other pilot in the cockpit starts the descent.
Then the other pilot comes back and starts knockly “softly” on the door and then he is heard banging on the door. According to the video he should of been able to get back in between 5 to 8 minutes later. Because he couldn’t get back in, it seems like an intentional lock out to me.
After watching the video, as I understand it, the door is locked from the inside and the crew has a secret code to get back in. The pilot inside has a switch to keep the door locked for up to 5 minutes, or maybe longer if its set differently? That’s how I understand it anyway.
But which pilot spoke with the ATC? If it were the pilot who subsequently exited the CP, that would at least better define the time line.