Partridge is on a field trip in the Personal Loss Archives. In the Archives, there are metal boxes that are labeled and alphabetized. They contain the personal items of the dead.
Partridge finds Sedge's metal box, but doesn't open it. The box says, "Cause: Gunshot Wound, Self-Inflicted."
Unlike before the Detonations, suicide doesn't have too dark of a stigma for those in the Dome. Sedge's suicide was tragic because he was young and strong, but taking your own life is seen as admirable.
Partridge then finds his mother's box: Aribelle Cording Willux. He is eager to open it, and finds a birthday card with balloons on the cover, and an old photograph of him and his mother.
He then finds a music box, and hidden under it is a thin chain of a necklace and a swan pendant made of gold with a bright blue stone for an eye.
He puts all of the items in his pockets, and then slips the metal box back into its place. Sneaky.