Due to the Spatial Power contained in that sea urchin-like item, the twins were not able to run into the Pocket Dimensional Realm. Usually, it would have been possible even in the face of Void Tempering Realm and even Space Bending Realm experts. Their Spatial Power wouldn't be enough to stop the twins from entering the Soul Gem Dimensional Realm since the entrance was located within themselves.
However, the sea urchin thing's Spatial Power was way above the Space Bending Realm. It was to the point that it was able to affect the entrance into the Soul Gem Dimensional Realm. Thanks to that, both Rean and Roan were hit by many spikes with tremendous Spatial Power and Soul Energy. They only had enough time to put their weapons in front of their heads, trying to stop the spikes from piercing through their heads.
*Cough, cough, cough....*
