So far, we have lost two aircraft and their passengers. That is a high price to pay. We may have lost them anyway. Certainly, this crucial circuit should not interfere with drills; with good design, it does not need to.
Its quite frankly ludicrous that you say its perfectly acceptable to make it impossible to turn off a piece of electrical equipment during Smoke and Fire drills.
All you are doing is replacing one major problem (the tracking question), with another major problem (sending those on board to their early demise through smoke inhalation and/or fire).
Quite frankly, I don't give a damn how good you think your circuit design skills are.....there will always be instances where the brown stuff hits the fan and unforeseen (or impossible to avoid) scenarios lead to the need to turn a piece of equipment off.