At the funeral above, no one could hear Loki's screams.
Some last, protective membrane of his cloaked it all in illusion. The other prisoners did not see him tramping about, ripping his hair, doubling over. In the locked box he created, he turned wildly, threw dishes, tore pages out of books and flung them against the wall. A scream slid out of him, but it sounded distant. His face, piercing, was lost.
The power flowed out of Loki as it never had before, in snaps and crackling bursts, like fire. It took over his brain. He was only anger. Chairs toppled, wood splintered, glass whistled and shattered and fell, and he felt pain. He threw everything he could, rent, shredded, frustrated, tried to topple the bed. Everything was met with his screaming. It rose and died, rose and died, infinite, keening.
Above, Thor and the others stood, cloaked in silence, holding lanterns under their arms. They mourned together. Loki mourned alone.
At the funeral above, no one heard him.