Other mistake: When the gate is activated (after O'Neill tells Woosley about the order to nuke the city), a member of the Atlantis team is on the bottom right, even though the Replicators have control of the city and no one from the Atlantis team is in the control room. This is because it's a reused establishing shot used throughout the series, including the series finale when the gate is activated (after Harriman says the Earth Stargate is offline).
Stargate: Atlantis (2004)
1 other mistake in The Return, Part 2 - chronological order
Starring: Jason Momoa, David Hewlett, Joe Flanigan, Rachel Luttrell
Visible crew/equipment: After taking the enzyme, Mckay is talking to himself as he dials the gate. When he goes to push the centre button, an arm moves on the opposite side of the DHD. (00:09:35)
Dr. Rodney McKay: All I know is that she's not who she's pretending to be.
Elizabeth Weir, Ph. D.: And you know this because...?
Dr. Rodney McKay: What, I'm not allowed to have intuition?
Elizabeth Weir, Ph. D.: You? No.
Irresistible - S3-E3
Trivia: Richard Kind who plays Lucius Lavin in this episode also appears as Gary Meyers in the original Stargate movie.
Question: Why can't they use every last iota of energy they've got and dial earth and ask them to send them any ZPM's that they could find?
Answer: Because even all 4 Naquadah generators (one was destroyed) together is only enough to dial Earth for approximately 1.2 seconds (As seen in the episode "Letter from Pegasus"). Further, if Earth had found a ZPM, they would dial Atlantis and let them know. After all, the SGC has no other use for a ZPM than to dial Atlantis.
Grumpy Scot