Archway Terminating Tube.
 

I saw this today at Archway...

The tube terminated at Archway and the driver did the usual walking
down the platform checking the carriages and closing the doors when one
passenger said watch this.
He pressed the door open button inside the car a few times (the doors
where already open) the group of friends laughed and said haha fool, he
said wait check what happens next.

When the driver got to that car to close the doors they didn't close
only the end door closed the others stayed open, the driver just
carried on down the platform checking and closing the rest.

He then got back down to his cab and closed the (remaining open) doors
from his cab. (the doors did the bleeping thing before closing)

2 Questions.

Why does this happen.

And
Should the driver have re-checked the cartridge was empty. Isn't it
against the rules to take passengers across the loop. (No one did
actually re-board the train)