Correct me if I'm wrong, but the captain calls for the evacuation not flight attendants. From what I've seen in training at airlines, the FA's wait for the captain's command for evacuation. The report states that the FA's were faced with lack of urgency from the captain to evacuate the aircraft.
Nope, I depends very much on the individual airline. During my initial training at one of the US big 3 airlines (with a hub in ORD), we were instructed that ANY flight attendant could initiate a full evacuation should he or she deem it necessary to save lives. One would activate the evacuation by activating the evac command button. This audible alarm would ring at every flight attendant station/galley and in the cockpit to indicate to immediately begin yelling commands to the passengers and opening all usable doors. Once the evac command was activated, a full evacuation was executed without
any questioning or debate....as in a 90 second evac/with full urgency.
We were told that the rational for allowing flight attendants to call for a full evacuation was due to past accidents in which the pilots were incapacitated and unable to communicate with flight attendants and the inability of FAs to access the cockpit in some situations. Also, flight attendants often have the ability to rapidly assess many parts of the aircraft that pilots may not. Any wasted time can cost lives.
I have heard that at some other airlines that their SOP is for FAs to wait for the pilot to give a evacuation command, except for extreme situations. I know some of these airlines have a 'code' word that the pilots will call out on the intercom to begin a full evacuation, particularly a low cost airline (with a hub at JFK). I don't think this is the safest option and could lead to FAs second guessing themselves or waste valuable time in conversation with pilots versus saving lives. I am not sure which of these policies DL follows.