Captain Jack Harkness: Under normal circumstances, an exuberant Roman soldier would be my idea of a perfect morning.
When the children are possessed by the 456, they're supposed to be frozen and stare blankly ahead. But during the second possession, as the camera is panning across a school playground, a boy on the far right is looking directly at it. As it moves closer to him, he swivels his eyes back to where they're supposed to be.
The hand preserved in a glass jar in the Torchwood HQ is the severed hand of Doctor Who which he lost in a duel during the Christmas special. The hand features quite prominently in episode 1 but can also be seen in the background in most episodes.