There's a certification standard to evacuate pax within 90 seconds using half the exits.
What's missing is a certification standard for post RTO checklists to monitor the fire situation and recognize when it's about to breach the cabin 90 seconds before that happens.
Any firefighter will tell you that fire behavior is highly unpredictable. The only certification test is for tire fires post RTO.
Cabin staff have a much better view of the situation and should be able to let the flight crew know when evacuation is required immediately.
Checklists need to provide for minimal delay of evacuations initiated from the cabin.