She was a prisoner in dark chambers

Something ran away. And came back.
Silence.
It was a metallic sound. No! It was something... dirty.
It was certainly attached to something. But it ran...
Again! It ran away! It just walked!
It came back! Then echoed...
And echoed.
Gradually, the thing came and went, and it echoed with heavy metallic sounds. I mean, dirty sounds. Organic sounds.
As time passed, the Thing had the opportunity to become familiar. And she was taken prisioner, and ran, and fled; she flowed here and there in some dark corners, always fearing something, never belonging to any place. She was a prisoner in dark chambers; she fled but returned, loved to have no place to live and hated where she was.
Certainly, she was running away from something horrible (and I am personally perplexed when I think): what would make the Thing flee for her life? Perhaps, the monster was a destroyer of worlds. A killer. An irrational beast. But what kind of disturbing irony could make the Thing always come back?
Who was the monster that pursued the Thing? Couldn't it be a bipolar lover? An angry master? Some lord who charges us with his debts?
My only true and logical assertment is that the monster is all of the above. It is the only rational explanation for the quasi-eternal fate of the Thing that began to flee yet always returns.
And now she was coming and going, fiercely. And the fiercer she got, the more familiar she seemed.
It was like hearing muffled, heavy footsteps in the rain. It was like the bloodstream. It was like the g...
Blood!
Of course! What else would be so dreadfully familiar to us, our Thing that flees and returns?
It is therefore to be deduced that the destroyer of worlds, the murderer, the irrational beast, the bipolar lover, the angry master, and the lord who collects the debts is... the heart. A human heart.
Gladly, if I may say it:
A human heart that worked.

JUST SOME INFORMATION: in the first chapter of the book, the main character is in a comma, his heart is not working properly. That is why I actually made a whole intro just portraying a methaphor of a heart that has just begun to work.
The book is going to be a sci-fi novel, but the intro is just a normal intro.