What do you exactly mean by 'running away'. Most, if not all, diesel
engines have some sort of governor controlling and limiting engine RPM.
Your problems sounds more like a faulty governor (if it is even that); it really would help if you answered never mondays (valid) queries for more info.
I do not believe you had a real runaway engine. Believe me I've seen one; we only managed to stop it by putting someones overalls into the air intake. Diesels can start running (away) if lub oil
is sucked in via bad turbo bearings or manages to find other ways into the intake (e.g. valve seals). It is a little rare. If it happens you will not be able to stop it with your normal fuel
cut off lever or button.
I guess it would also run away of the IP malfunctions; judging from the info so far I think this is not the case.