Damn...
-----< SPOILERS >-----
A short story shows Humans who have died helping the one who just died. Then we get to see a little girl's last moments and how she died. She believed till her last breath her mother was the best, little did she know how she was bullied all her life by her own mother. Shimura said well it is all brainwashing. The child was brainwashed from the start into believing she was a bad child and her mother just punishes her when she is a bad child. [All children are innocent and what you teach them is how they will grow up to be]
Right at the end, we see the helpers discussing how who gets to work there. The topic is whether the girl's mother will end up working there or not. And with the conversation we learn that only people on the death penalty are selected to work here, hinting that the Shimura and Ishima were both on the death penalty, thus leading them to work in the DEATH HALL.