Shingi felt disappointed that he failed to release the Energy, but it wasn't like he didn't earn anything from it. On the contrary, he had shortened his time in the Darkroom by many days and could feel that the time he spent with the strange Energy helped him understand its nature better.
'Next time, I should be more prepared for it.' [Shingi]
Even if he wasn't sure what would happen if he released the Energy, there had to be a reason that it was there. He could tell that breaking the field wasn't impossible, but he didn't have enough time to find the solution.
After all, even the Invulnerability State was considered impossible to deal with, and they could escape from it, but he broke it. Still, dealing with that field was even more of a challenge since Shingi had no access to his Skills.