Leaving the energy released by the jellyfish in the void would only allow it to disperse. Noah couldn't contain all of it even when his ambition empowered the dark world, so he had to absorb it inside the black hole to ensure that he didn't leave anything behind.
An immense pressure started to build inside Noah. He had been the first expert to reach the corpse, so he had managed to absorb the biggest share of energy. Yet, that power could fuel a rank 9 creature, and even his incredible centers of power fell a bit short.
The black hole struggled to contain that massive wave of energy. It couldn't purify it in its current state, and its edges inevitably grew unstable. Those instabilities then spread toward the rest of Noah's body and made his flesh shake.
Still, Noah didn't stop. He knew how resilient his body was, and he couldn't let that energy disperse either.