Referring back to why the Engine Fuel Switches are placed to OFF before the Fire Switches are pulled, on the 737 CFM (300/400) the Engine Start Levers shut both spar and main engine fuel valves, whereas the Fire Switches only shut the spar valves. I remember a crew I was training forgetting to move the Start Levers to Cutoff following an RTO and Evac scenario and wondering why the engines continued to run for about 12 seconds........
Good to see that on the newer Boeings the Fire Switches shut both valves.