Noah healed himself in the dark, and while he did, he fortified the prison.
The heart came back together under the flood of his Infinity, the ruptured organ knitting around the swirling rune, and he did not stop at whole. He poured more of himself into the cage, thickening the folded chains, deepening the layers, taking the lesson THE Sealed One had handed him in blood and using it the way he used everything.
The thing could break his heart on a whim. So he built the cage to hold even through a broken heart, made the seal a thing that did not depend on the organ staying intact, anchored it instead to his identity, which was the one part of him nothing could rupture. If it wanted to make his heart its weapon, he would make sure the weapon cut nothing loose when it fired!
And as he worked, the records surfaced. The knowledge he had been drawing out of the chained thing beat by beat, the slow theft running underneath everything, brought up something usable.
