Preston, Jessica and Gracie's fates.

I don't get it. Preston was nice so prototype turns him into an immovable little catbee. Jessica was not nice so he killed her. He hated Gracie so he turned into arguably the most tame and human looking toy with pretty cool abilities and left her alone in isolation in her own dollhouse, where she is allowed to roam freely whenever she wants and all that because killing her would be too merciful.