I like your mention of the word armor, that fits with a guarded heart, and with the concept of a Tin Man, and with the suit. And the 'us' v 'them' you mentioned is really true, you said: He's unaffected by Raw's plight because Raw is not yet someone under his protection. That did strike me as really harsh of him. It's also in keeping with his 'don't trust anyone in the O.Z.' advice he gave DG, which leads me to think he was betrayed by someone. Maybe Zero had been a Tin Man and pretended to be his friend/ally, and then betrayed him?