I can help you make that happen.
My first thought is the exact same as yours.Just have a light beam hooked to a relay, when the beam is broken it could trigger the relay which fires the 88. This system is readily available with lots of automation companies that build robotic safety enclosures. When the beam is broken the relay triggers a shutoff on the machine.
Would not be hard to do at all, distance the beam would carry would be sufficient enough yet it would not cut a path clear across our field either making it fair.