I was taught that once the engine started in the 172, you should pull the throttle back or adjust to about 1000 RPM immedietly and monitor for oil pressure. Sometime if the plane doesnt start, while cranking, Id move the throttle in and then pull back when it gets going. Im thinking, that if his brakes were set according to the checklist, he would have had just enough time to stop it in time, maybe that was the problem? I dunno

But ya, always follow checklists. Going over them over and over again, theres still room to forget stuff.