When Ianto tackles Jack outside of the Cyber-conversion chamber, the close up shows him as being pushed into the wall. On the wide shot, however, he has been pushed onto the door. (This was because John Barrowman and Gareth David-Lloyd broke the door on the first take, meaning that they had to change the position for the close-up).
Jack's original line to Ianto after he says "You hid a Cyberman in Torchwood and you didn't tell us?" was supposed to have been "What else are you hiding in our basement?" The line as shown, "What else are you keeping from us?" has been overdubbed, as Jack's mouth doesn't even come close to matching the line as spoken.
When Jack Harkness points the gun at Ianto, Eve Myles can be heard saying "John, what are you doing?". Hearing his own name instead of his character's clearly makes John Barrowman stumble his next line, "Resisting the urge to shoot". Eve's flub appears to have been corrected in later Blu-Ray releases, as she can be clearly heard to say "Jack" on the audio track.
When the pizza girl delivers the pizza, she only has the two boxes. She isn't carrying anything that would resemble a coleslaw container, which Ianto ordered at the beginning.