If I recall correctly, re the Manchester accident, the wind was barely five knots but because the 737 was stopped 90 degrees to the wind and the fuel was pouring from the left wing area at 2000 kgs per minute and igniting, the slightest wind wafted the flames into the left side of the fuselage and breached the fuselage at passenger seat level.
On a dry runway an abort using RTO brakes, spoilers and one thrust reverser, is worth 170 feet less than a brakes only, spoilers, no reverse. This would suggest that if an engine fire was the reason for an abort, then rather than pour more power into the flaming engine by using max reverse, the extra runway savings (170 feet) in terms of length and time is simply not worth the risk of stoking the fire.
Thus it could be argued that it might be a safer option not to use reverse on the engine that is on fire. On a wet balanced field length where brakes are less effective, then one would have to re-consider the options of reversing an engine on fire.
In the simulator exercise the crew hear a bell and see a little red light in the fire handle. That little red light could mean a blazing fuel fed fire in the real thing. But the simulator can breed a false sense of security because the pilot knows the fire is not real.
This can lead to complacency if the real thing occurs in an aircraft. Speculating for a moment - If you knew for a fact (via ATC) that you had an engine on fire and were aborting, would you really want to set take off power into a burning engine (which is what you are doing at max reverse)? And for what gain?