--
Cedric secluded himself to practice in an isolated room.
He ensured that not even a sliver of whatever he's doing outside would leak out, not because he's afraid of damaging his surroundings but because he's practicing spatial manipulation. He couldn't risk being discovered while doing this, or else the Demon Race would never let him know peace.
Sure, he could've entered the true Sword Communion Hall to do this; he just chose not to. Whenever he's in there, he's unable to prevent himself from being immersed in the profundity of concept laws. He'd end up spending months in his immersion, getting no practice in, and that just won't do.
The application of concept laws is just as important as comprehending their profundities. There has to be balance, or else he'd drive himself into a bottleneck. And at times like this, where he needs to have steady growth, bottlenecks are no good.