Silence
Kristoff hadn't been uncomfortable in silence for a long time. In the mountains, silence was to be feared. In the palace, silence was to be treasured. Quiet moments curled by the fire meant they were alone.
This was not comfortable silence. It was heavy and broken and filled with pain. The air buzzed around him. The room was dark and cold. He remembered it being alive before; always alive. His heart constricted, squeezing a gasp from his lungs. There was supposed to be a fire burning, there was supposed to be Elsa sitting on the chaise reading a book. Anna should be laughing with him.
Everyone was still outside. He knew he shouldn't leave Elsa alone to deal with this. He knew he should be down there. But she shouldn't be there. She shouldn't be so quiet in that box. She shouldn't be so still in that hole. Anna wasn't supposed to be silent.