FlameWheel F-450 with KK5.5 Controller one ESC went up in smoke!

I was flying my F-450 this time with a KK5.5 Flight Controller and one of the ESC's went up in smoke.  This is what the guts of the ESC looked like afterwards.

Here is the video.  I am still learning how to fly this thing.  It takes lots of practice (and crashes).