I recall being trained to mist the area...approaching from the front or rear. Not from the sides. Thermal shock from a wet product is just plain dangerous unless it is vital to stop the fire spreading to the main hull.
The thing is that the prop has to be stopped, so a little longer delay perhaps, but given the fire is correctly reported to the flight crew, then time is of the essence.
As far as I can make out, this fire was progressing steadily, and might have responded well to quick action while in its early stages.
After some years of experience, I always had a cunning plan to call on if a fire was reported. By this I mean a place and angle to turn to so that the fire was in a downwind position. Not always possible I know, but such a tremendous advantage if such a manoeuvre can safely be implemented.