Could passengers realize a possible emergency? First, to clarify, I'm not looking for nightmare stories here. I'm not curious about the fears of passengers but rather about what's actually noticeable for them. It's pretty clear that passengers not flying too often tend to be afraid during turbulence. But, I suppose, very few of them ever experienced a stall or similar.

Now, reading about crashes like the one of AF447 where a pilot only very late in the emergency situation re-enters the cockpit, I'm curious about why that is. I've never been on a plane during a stall, let alone an airliner. Don't passengers (and thus a pilot outside the cockpit) experience a stall as something very unusual, dramatic event? As another example, the crash of 4U9525 which was, as I understand it, a very "common descent": could a passenger even notice a difference between the upcoming crash and, say, an emergency landing at a close airport that the pilot just didn't have the time to explain beforehand?

Given "weird feelings" during flights, often related to turbulence which is not at all dangerous -- can a passenger "feel" the difference between those, a controlled flight into terrain, and an imminent crash?

Update

I disagree with closing this questions as a duplicate of What things can a passenger look out for, to indicate an emergency?. I was not looking for how passengers could intercept with flight management. Let's make it more concrete with the AF447 example then:

According to Wikipedia, about half a minute after the problem of wrong speed indication occurred, the aircraft went into stall. Another three minutes later the now returned pilot realized the stall only after he was made aware of the PF pulling up the whole time. Given this example, does a stall with an A330 feel so much "normal" that even a highly experienced pilot couldn't "feel" the missing lift? Will the passengers have thought the flight was still normal at this point?
One of the survivors (a passenger) of Air Florida Flight 90 was a Private Pilot and


  ...Stiley, a pilot himself, said he realized that something was wrong as the plane headed down the runway. He said there was still snow and slush on the wings and he remembered wishing he could get off the plane.


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