If the engine starts and stays running, air in the fuel system isn't a problem. Cover the air intake with a block of wood or computer mouse pad - something the engine can't suck though the manifold. That's the quickest way with a runaway. If it's just idling along and a sharp jab of the stop lever doesn't do it, loosen the injector lines until the engine stops.

Has anyone tried discharging a C02 fire extinguisher into the air intake of a runaway? Or even Halon?

Sixto
83 300SD