Testing the fire system after a fire drill is one I teach as well. I have practical experience of just the very situation where the fire loop got taken out when a combustion can on a RR Dart blew and caused the fire warning to go away before the fire was out.
But like GC, I would not condone 'creative' departures from the QRH just for the sake of it. Not all pilots are particularly knowledgeable of systems and so the QRH is written for the lowest common denominator for good reason. It is when the situation is NOT covered by the QRH that one must use common sense and airmanship and whatever other resources are at hand. But in today's litigious society it would be a brave pilot that stepped outside SOPs and QRHs etc without compelling reason.