a little help if you can,

i mate of mine is after killing the ignition on his engine when changing gear, car is a evo 6 it uses a ikea shifter with trip switch for clutch and for ignition kill if needed as it has non mechanical clutch setup,

can we just kill ignition via crank sensor or just kill two cylinders on a coil pack? or kill all the coils? what is the best way to sort this

thanks