There was one thing that might have been a problem. How would they separate the Fragment from the Core? If the Core could even resist the destruction of a Dimensional Realm, then acquiring the Fragment inside wouldn't be easy. It wasn't like the Purple Crystal that could be absorbed.
However, there was indeed a kind of force that would definitely succeed in extracting the Fragment from the Core. Obviously, it was the presence of other Fragments. To be more specific, nine Fragments that were now part of the Foundation Pillar inside the Soul Gem Dimensional Realm. The pulling force that they will exert on the Fragment inside the Core would be no joke.
That's why Sister Orb opened just a tiny, tiny path into the Soul Gem Dimensional Realm. That path was way too small for the entire Core to pass through. The Fragment would be pulled from within the core since it was the only thing small enough to go through the passage.
*Bang!*
