Momoka miscalculated to think the other swords weren't as important as the others.
The Dual Swords especially got made from Nullifier by matching the Rare Mana characteristics of the two Spheres.
The sword that Momoka didn't pick up was the one that gave Ji-woo the ability to open the dimension of space. That was why he could appear in the blink of an eye without any sign of running or jumping. Even though the distance to change places in an instant wasn't far, it was sufficient in combat. The only drawback was that the ability couldn't get used in a row. There was a cool down to be able to use it again.
Momoka should have disarmed both weapons regardless of the direct impact of one of the Dual Swords. Well, in the end, it took his life. Even if the two swords got taken from Ji-woo's hands, he still had no chance of winning.
Ji-woo was at his pinnacle. It didn't have any downsides at all, even though the power got used by force.