Why didn't the passengers do anything?
In a word, intimidation.
The hijackers learned that by having a very large number of operatives onboard, acting 1) boldly, 2) well choreographed, 2) in a very aggressive manner, they would be able to intimidate everyone: Passengers, crew, and Air Marshalls combined.
This is not a good indicator.
Now, before you start quoting me chapter and verse from the Gospel According to Flight 93, remember that even with that flight -- which was followed a very different model, i.e., much smaller number of hijackers, all congregated around a single focus of attack (the cockpit), and, they'd actually taken over the plane, the passengers remained passive, UNTIL they learned of the WTC horrors.
It was then, and only then, that their adrenaline kicked in, and they went for broke.
The enemy is not stupid.
He is evil, evil beyond comprehension -- but he is not stupid.
The enemy has learned some lessons in the years since the last major attacks. And, it is obvious that this flight -- and several others like it -- using various probing tactics -- were a learning tool.
And it is equally obvious that they have learned that a certain combination of factors will allow them to gain "total air supremacy" over the plane. This is obvious, because they did gain total air supremacy over the plane discussed in the article.
They held everyone in check. No one would make a move on them, even though they were all scared $#!+less by them.
If it had not been a probe -- a test -- it would have been a nightmare. She said that there were people on board "higher up than you and me watching the men."
Oh?
Watching, were they?
A fat lot of good that will do in a real attack.
And remember, the ONLY thing that diffentiated this hijacking (and make no mistake -- that's exactly what it was, albeit of a transient nature) from an attack was the fact that the hijackers were "firing blanks."
If they'd been assembling actual explosives, it would have been a horror beyond description. And NO ONE would have stopped them. And that was the lesson they learned in the probe. They learned that with sufficient numbers, with sufficient aggression ("power stares" etc.), and with sufficient choreography, they will succeed in intimidating everyone on board, from the meekest passenger, to the crew, all the way up to the FAM pair.
Like I said, be afraid. I certainly am, and I don't scare easy.
Be afraid.
We all need to be "very afraid".