It was only when the giant got halfway down the incline that he suddenly,...

It was only when the giant got halfway down the incline that he suddenly, happily, burst into flame and continued his trip saying, "NO SURVIVORS, NO SURVIVORS!" in a manner that could only indicate deadly sincerity.
It was seeing him happily burning and advancing that startled the Brute Squad to screaming. And once that happened, why, everybody panicked and ran...