This one comes up fairly regularly at work as a discussion item.
I think it’s one of those “it depends” scenarios. If I was rejecting at LHR (or LAS, given their demonstrated performance) due to a fire warning, I’d want to stop as quickly as possible and leave as much room for the emergency vehicles as I could as I know they will be there very quickly.
There is also the issue of *how* to position the aircraft. Do you let the auto brake bring it to a halt then set off again or do you take it out and manoeuvre? If you haven’t practiced this it may be more difficult than it appears and will certainly delay an evacuation if required. Cabin crew with some operators are authorised to initiate an evacuation in “catastrophic” situations: flames running up the side of the aircraft and possibly smoke coming in through the AC would probably trigger this, especially if the aircraft has come to a halt. Setting off again with the slides trailing behind you and and people trying to use them is not an ideal outcome.
If it happened at LOS instead of LAS, I think I would be more proactive in aligning the aircraft as you have to assume you’re on your own.
As far as the Airtours 737 goes, one of the major points was that it took a long time for the aircraft to be slowed to a halt plus the runway was vacated, all the time while the (external) fire was burning fiercely. When they eventually stopped, the whole thing was well alight and fuel was pooling underneath. In light airs, a large fire will draw in air from all directions, creating a local wind.
In summary, I think it’s a good point to consider but there are other factors that may override it as an SOP, such as a big aircraft and narrow runways. Also, if you are unfamiliar with the manoeuvre, it may not go quite according to plan.