I never tell anyone or even advise anyone to defeat a safety switch no matter how stupid & useless it is like the MIR system.
I will tell you how it works. what you choose to do then is your business.
Somewhere there is a plunger switch which when activated will either make a circuit or break a circuit.
It has to be placed somewhere easy to access where a control arm can hit and depress plunger.
So the best place is on the tranny.
Usually it will be a normally open switch so an arm depressing the plunger closes the switch and creates a ground path for the magneto coil which kills the engine.
Better ones use a relay to power the blade clutch & the switch trips the relay to turn off the blades.
They are always ground circuits