A saw comprises a surface having an opening defined therein, a plate structure configured to be attached to the saw below the surface, and an arm pivotally attached to the plate structure about a first shaft. A blade is configured to be engaged with the arm at a location spaced from the first shaft. A portion of the blade extends through the opening when the saw is in a normal operating position. The saw comprises a firing mechanism comprising a barrel end portion having a bore defined therein and an extendable piston at least partially positioned within the bore. The barrel end portion is attached to the plate structure. The extendable piston engages the arm during its extension and causes the arm to pivot about the first shaft when the firing mechanism is activated by an activation signal. The pivoting of the arm causes the blade to be moved downwardly below the surface.