Is depressurisation the answer?
 

A thought. If you're hijacked perhaps depressurising and staying high is the answer. It would either kill or knockout the hijackers if they failed to put a mask on or it would imobilize them because they would need to keep a mask on. It wouldn't stop a bomb, maybe, but it's an idea. You may then be able to move about with the portable oxy bottle and "tke care " of the bandits. With a crowbar to the head.

I honestly don't think there is any mileage in discussing potential solutions here as we are not a secure site.

In-house discussions with your own airline management team is the way forward.

I STRONGLY RECOMMEND THAT WE REFRAIN FROM POSTING ANYTHING WHICH, POTENTIALLY, MIGHT REVEAL A WEAK AREA IN AVIATION SECURITY.

It would be far better, and more professional, to report the matter to our individual aviation authorities, airlines and pilot associations confidentially.