Crazy Situation - Need opinions

[Chukinrox]

This occurred in a game abotu two weeks ago.

Bases loaded. No outs. Batter hits a grounder towards SS. Runenr from second is goign towards third and his helmit falls off. The ball goes INSIDE of the helmit causing it to spin. When the helmit stops spinning the ball is still inside. After 10 minutes of discussing the play and making a few phone calls to find a ruling, the umpires ruled it a ground rule double. How they came up with ground rule double..... I HAVE NO CLUE. I would say the helmit becoms part of the playing field if the ball did not become lodged in the helmit. Since it was inside the helmit the ball has to be called dead right away, but how can you award the offensive team anythign if the ball became dead because of the offense? Any Ideas?