The soul reapers' jobs was to save the souls of the dead by putting them with their families in the afterlife. If they did not, the souls would be lost forever...
It was just another day as he was started to get complacent. He was starting to have a hard time keeping up when he saw one soul float away while he desperately held the others. He was angry with himself for letting it go. It was a young boy's soul that will be lost forever. He had one job like everyone around him and failed. He would soon go back to waiting to redeem himself.
Yet he could only think of the young boy's soul that would never be with his family in the afterlife again.
He had to save the young boy's soul, wherever it went. The soul reapers were never told what happened to souls that were not put with their families. He never could have known how far he would travel to get the boy's soul back.