It doesn't dump the belt.
I'm pretty sure it has something to do with killing the tires and hitting the limiter. Interestingly enough, three turbo ls cars here locally had the exact issue, which was fixed by a billet tensioner.
The stock tensioner looks, and functions fine, but I believe it was allowing the belt to dance, and eventually work itself off and shred, thus taking everything along the radius of the pullies with it.