Could you wire a 12volt relay, coil to the buzzer normally closed contacts to the ignition coils, that way when the buzzer goes off the relay kills the spark.

I was just curious because when my secondaries got stuck open, the engine went way above redline a few times. (Not longer than a few seconds though. I pulled the key.)

 

I don't see why it wouldn't work? Try it and find out. haha... that's my motto