MMM/2650 + Slash 4x4 = FIRE!!

[kazuaki]

I have been patiently waiting for the new Slash 4x4 to be released. When I heard about the Platinum Edition, I cancelled my preorder of the RTR and ordered the PE instead. I finally go the truck on Monday. Traxxas set the truck up to accept the MMM combo, so I installed a brand new MMM/2650kv combo from the get go. I connected a brand new Hyperion G3 VX 4S 5000mah pack. The truck ran great for about 45-60 seconds, then the ESC burst into flames. I've never seen an RC vehicle on fire before, but it was scary and the smell was HORRIBLE. Anyway, I was able to blow the flames out within about 20 seconds. I've included pictures below (cuz everyone loves carnage), but please also take a look at my questions.

1) What the heck could cause this?

2) Obviously the ESC is toast, but should I be worried about the motor? In the Slash 4x4 the ESC and motor are pretty close together and the endbell of the motor is blackened from the fire.

3) Is there any way to be sure my lipo is OK? It doesn't have any visible damage and it still reads full voltage.