We've had a good run of luck
Recently a number of airframes have been seriously damaged or written off by fire without losing any pax.
Going back a few decades shows a less benign record. Some of the reduced fatality count can be credited to improved design of fuel systems and structures. But some day there will be another major fuel system breach with the wind blowing the wrong way.
In that case the fatality count will be a function of delay in beginning evacuation.
I propose that RTO SOP include cabin crew at the rear stations as they are best positioned to observe the gear and wings. In case of any flames, the rear crew must have an open line to the cockpit.
Cabin crew training needs to include fire assessment and knowledge of fire propagation. They need to be able to distinguish between tire and brake fires that certification allows time for ARFF to get on the job and fuel fires that are being blown towards the the fuselage.
Report of a fuel fire should interrupt the cockpit checklists in favor of immediate shutdown for evacuation.
Admittedly fires can either die out on their own or rapidly develop into a major conflagration. We only ever know after the fact.
Elderly and fragile pax are usually the last in line for evacuation and most prone to injury going down the slides.
Once the able bodied are off, there might be time to reassess the fire danger, especially if ARFF is on the scene and getting the fire under control. But remember that most fatal fires have exacted their toll before ARFF is on the scene.