In the cockpit, you have two guys trying to assess, communicate with the cabin, make a decision that almost inevitably results in some kind of injury, and execute a 10 to 12 step checklist in an orderly manner...
In the cabin, you have 7 FA's and a boatload of pax awaiting a decision when it is painfully obvious to all what the answer is...this kind of intense pressure bears totally on the cabin crew. Given the obvious next move, obvious even to your average low-information passenger...you know, with the right wing fully engulfed in flames...how long should they wait?
There is no right answer. Bottom line is everybody got out. It wasn't necessarily as pretty as we might wish, but it worked. Now we need to think about how we get the cockpit SA and the cabin SA into alignment a helluva lot quicker.
One way is through continual monitoring of the cabin interphone with an SOP that says the cabin can simply pickup the phone and start talking...without all the chimes and secret signals...thus aligning the cockpit SA more quickly to what is going on in the cabin.
I will simply note that such was the SOP at this particular cockpit crew's previous employer...but that is not the SOP at the current employer...