This post, about the "2 in cockpit" rule, was disallowed over on the "Main" thread.
Why did it take this event to have it put in place everywhere?
Because the chances of such an event happening are vanishingly small.
And when you must treat all employees with suspicion, where will it all end?
What if it is the FA that is ushered into the cockpit that turns out to be the suicidal actor, and attacks/incapacitates the co-pilot when drafted in to the cockpit? Even if they didn't know before, they now know how to lock everyone else out.
What if the FA and the remaining cockpit crew member are co-conspirators?
How can either occupant stop the other, if they are determined to use violence to achieve their goals?
Do airlines conduct the same psychological profiling on their cabin crew as they do their cockpit crew? If not, why not?