It has a rev limiter on it and my son does not hit the rev limiter on this track when I take it out I can hit the limiter but I have only driven it for maybe 4 laps a few weeks ago. I think the limiter is set to 7,200 RPM's and this is set by Briggs.
It looks to me like the cylinder portion of the engine tried to launch off the top of the crankcase.
Here are pics of the Piston top and the head:
