Even more so: Keeping the shades open could have really made a significant difference in this case, because it could have helped the flight attendants to quickly determine the exits that are safe.
For obvious reasons, ordering the evacuation, in conjunction with criteria such as which side and which doors is the Captain's job, or if the Captain is incapacitated, the First Officer. They will have access to far more data than the cabin crew will (e.g. whether the engines are safely shut down, circumstances on the ground thanks to radio contact etc.).
The Cabin Crew will not make the decision themselves unless they have been unable to establish contact with the cockpit (i.e. both flight crew incapacitated). In normal circumstances the Cabin Crew are only there to action the Flight Crew's orders.
Communication is key, but comms might have been down, too. In cases like this the cabin crew have to be prepared to initiate an evacuation on their own, and they have to be prepared to choose which doors to use.
Re-read my post, because your conclusion is saying exactly what I already said with your words "be prepared to".
To repeat what I said, but in simpler terms:
In an ideal world, the Flight Crew have the responsibility for ordering evacuation and the associated parameters. End of story, no argument.
BUT there is a well rehearsed, well practiced, protocol which surrounds this !
So, at one extreme, if the Cabin Crew cannot communicate with the Flight Deck, then the decision is clearly theirs.
But before the extreme, we have the obvious scenario .... Cabin Crew act as additional eyes and ears for Flight Crew.
BUT in this scenario we are back to my main point ... the buck stops at the Captain to make the decision !!! The Cabin Crew are telling the Captain what they see, its ultimately his call.
> They will have access to far more data than the cabin crew will (e.g. whether the engines are safely shut down, circumstances on the ground thanks to radio contact etc.).
This is not remotely guaranteed. It would be more accurate to say that the pilots will have access to information that the cabin crew don't have access to and vice versa. If the cabin crew sees that the plane has stopped, there's a fire on board, and instructions are not forthcoming from the pilots, the cabin crew absolutely must initiate an evacuation sua sponte. Heck, if the cabin crew won't do it then the passengers might. People can and do freeze in the face of emergencies. When you have a fire on board all bets are off, and someone had better step up and begin the evacuation -- better that it all be orderly than not, but also better that it happen at all than not.
>In the meantime, the cabin crew had been attempting to get the pilots’ attention using the emergency call button, but all the pilots were so focused on the failures that they initially didn’t notice. Only now did they send Second Officer Mark Johnson to assess the situation in the cabin, whereupon a Qantas pilot riding as a passenger in the upper deck drew his attention to the in-flight entertainment system, which featured a live view of the aircraft from a tail-mounted camera. The digital stream clearly showed a much more literal stream of fuel pouring from the left wing and into the aircraft’s wake, which was also visible with the naked eye from the lower deck. Johnson proceeded down to check for himself, at which point he also observed for the first time that there were two gaping holes in the top of the left wing, surrounded by jagged metal, where the turbine disk fragments had exited.