positive air valve...
If your totally spooked about it,you can try and pick up a positive air shut-down valve...it's basically a flapper valve(guilotine style) that is spring loaded,and trips when a cable is pulled or a solinoid is switched.
we have to have them on all our diesel equipment that we intend to operate in gas plants or refineries,just in case a nearby gas leak starts to fuel the engine externally.it's amazing what a diesel will run on...h2s,natural gas,hydrogen,methane,propane...you name it.the valve totally blocks the intake...nothing gets in,so no air,which means no fire.
www.roadadeaco.com makes a good one.thev'e been around for a while,but certainly aren't the only manufactuers out there.some of the latest can be shut down wirelessly,by remote.a new one (deuce sized) will cost some serious coin.anyplace that sells used heavy truck parts might have one on the shelf gathering dust
and yes...a runaway 6-53 is an awsome thing to see.and hear!sounds to me an awful lot like a blown dragster at end track,followed by some horrible mechanical noise...rare though.way less common on four strokes,turboed or not.todays turboes are way more reliable than the early ones.
also...if your looking for a security measure,a tripped air valve means the engine absolutely will not start.some thief fumbling around in the dark trying to steal your deuce will never find it,or even know what it is.as a safety measure at a show,a tripped valve means that no child or sticky fingered kid who happens to see keys will be able to start the truck.