Well actually a lot more can be said Dome.
I used to fly 72s for the United States Marshal Service. We tried to make the cockpit door to be protected against any type breach.
What we discovered was with enough time no matter what we did to protect the door the “bad guys” could gain access. There are enough tools in the cabin of ANY airliner that can be used to force the top or bottom of the cockpit door open.
Therefore the ultimate answer was to have a firearm in the cockpit. I can’t tell what we did because it is still controlled information. But we were comfortable with the end result.
The bottom line is “Arm the Bloody Pilots”. As in Period!
Sorry anti-gun folks, but sometimes the truth is not PC.
Ps. We can’t put all of our passengers in handcuff, waist chains and leg irons, even how bad sometimes we want to!
Now understand I am not defending this guy. Ok?