Unlike the slaves in the Myriad Puppets Pavilion back in Veluriyam Capital, these ones didn't wear any masks. Otherwise, Jiang Chen wouldn't even haven't looked at them. However, he didn't lower his guard even if their faces were exposed in broad daylight. Seen from another angle, the Great Scarlet Mid Region being so straightforward and completely exposing these slaves' faces might be a trap designed to lure their enemies with.
He was originally planning on buying all Regal Pill Palace disciples if he saw any. But thinking carefully on it now, it seemed very dangerous to do so. In case it turned out to be a trap, he was bound to attract attention if he only bought disciples of the Regal Pill Palace and no one else. After all, who would be so kind as to buy disciples of the Regal Pill Palace only, if they weren't a disciple of the sect themselves?