Continuity mistake: In the scene on the pier with Toshiko and Tommy, the soldier from WWI, Toshiko is holding her hand bag but drops it when he picks her up. Immediately, the next shot she is holding it again.
Continuity mistake: Gwen views a transparency of two Torchwood members from 1918. The words "Torchwood" can be seen behind them. When Ianto takes the transparency and holds it up, the slide is different: it contains five people and the word "Torchwood" is above their heads.
Answer: He might have requisitioned or stolen it from Torchwood London, or he might have been ready down below once it'd been severed, searching for "the right Doctor" and not knowing that the newly-regenerated Doctor was the one he was looking for.
Captain Defenestrator