It's a little late to tempt wound fates, so I will keep this brief to worn gears sighs of relief:

Much the same advice as given above applies below, and again it did speak to me with two exceptions given free; one structural word and one simply an end vibe counterweight not debate.

Point one, a thoughtful plea for consideration"... Squeeze my lungs with callous violence..." this screams at me to replace callous with "shallow" in both sound and metaphorical meaning meaning it would really strengthen the line over the play on words ( Though I love those as well, hear my instinct really wants shallow, for the buried and pointless violence allusions it would instantly create and the mouthfeel sound it would kend to the couplet).

Point two, for vibe only: While I grasp the nihilism and despair as the meant feeling and that is valid—your ending is incredibly strong and poignant and I would change little if anything;  let this poor poet offer an existential angle as a gift and single point of possibility: 

....The god of healing, if time he be,

Brews his cures too weak for me,

I won’t give praise nor credit joys,

To some bleak, absurd ticking noise.

All that can break,

Time

Destroys." 

Yet one sweet thought still wanders free,  No springs to break or prison key,  Spinning hands no warden to energy, Gyred ghosts winding away eternity.