Late night guess...Quite possibly wrong....but the inner cv joint could easily break on just one axle. The inner cv joint most always being the weaker of the cv joints.
Edit: 11:48pm PDT....after reading this about helical and Torsen differentials:
"Locking on throttle but requires both wheels to be on the ground"... from here:
http://www.trak-life.com/basic-intro...erentials-lsd/
So if one axle or cv joint is broken, it's as if the wheel/tire on that side of the car is 'off the ground'
And if the inner cv joint broke, chances are real good... it also tore open that axle boot (rubber).