Hmmm... I thought I'd ditched the breastplate idea in favor of the two, wide bandoliers covering that area...
Let me dig into my write up...
If he does have a breastplate, then, yes, he'd probably have removed it before zonking out; however, given his love for the fight and the urgency of the sounds downstairs, I can totally see him having neglected to put it back on.
Edit: From my original description - "His broad torso is criss-crossed by a pair of wide, leather bandoliers, studded with steel and bone in which his curious, sickle shaped sabers (called falcata) are sheathed when not being employed with deadly effect by the Capashan Cat. Belted about his hips is a distinctly kazari garment called a dak’tar; essentially a skirt of leather strips, studded much like the bandoliers, that serves to protect the upper legs and allows his long, lashing tail to remain free. The kazari’s powerful forearms, too, are wrapped in bracers of the same bone-studded leather as the rest of his garb but, beyond these items, Ch’dau wears no true armor to speak of (though it appears not to trouble him even when faced with battle)."
I think I foreswore the breastplate.