Westhawk - you are absolutely right and your comments reveal a succinct clarity of the security environment in which we now operate. No Commander of a commericial aircraft should ever concede control of the flight deck to an intruder under any circumstances. As others have pointed out, prior to Sep 11, the imperative was to prevent loss of life or injury to your passengers and crew. That lead to a policy of basically doing what you were told by the hijackers, getting to a suitable airport ASAP and letting negotiatiors sort it out. We now know that such a position is no longer tenable given the stated intention of some Islamic terrorists to kill every person on the aircraft and as many people as possible on the ground. In the light of such a potential catastrophe, the need for the crew to remain in one piece is far outweighed by the need to regain control of the flight deck. Therefore you have to do whatever is necessary to regain that control.
These battles are won beforehand in your mind - not when faced with an intruder that you are subconsciously willing to consider may be just an 'ordinary' hijacker rather than a mass murderer. Nobody wants any conflict, particularly of a violent nature, but you simply cannot take the risk that an intruder is someone you can deal with by negotiation.