Id venture to say the same thing is quite possible with the stock plastic hub on a T-rex too.
Both the T-rex and the MX400 have a lot of power under the hood. If you dump all that power in an instant....stuff is going to break.
If your head didnt shear, you probably would have at the least taken teeth off the main gear. Even the little E-flite Blade CP will eat teeth off the main gear if you jam the throttle stick to full throttle really fast.

Dont be so quick to blame the heli, when it was your mistake.