Actually, speaking of the destruction of the Hub, I'm surprised the Black Ops only found Jack's body parts. Many of the past members of Torchwood who died in the line of duty were kept in a crypt deep within the Hub, including Suzy Costello. And Jack's brother Grey was there as well.
Plus there should have been at least one Weevil down in the cells.
How convenient then that the Black Ops found Jack's arm out of all of that....