When the Divine Condor brought Yeung Gor to the Tomb of Swords for the first time, Yeung Gor saw four swords on display...none of them sheathed, and no sheathes evident in the vicinity.
It appears that the Sword Demon was not a believer in sheathes. That, of course, is different from 99.9% of wuxia swordsmen. The only other swordsman in wuxia I can think of who eschews a sheathe is Ah Fei from Gu Long's LEE'S FLYING DAGGER stories.
Perhaps Dook Goo Kau Bai found sheathes to be an unnecessary encumbrance?