Basil
I. The captain, or Pilot in Command, is not 'in charge' of the aircraft; the captain is 'in command' of the aircraft.
2. The dispatcher (or whatever the person in charge of boarding is known) is responsible for the boarding process.
But the issue seems to be who is in charge of any de-boarding process? Firstly in the event of a mutually agreed departure,
and secondly in the event of a stand-off.