At the beginning of this episode, there are images of the Russian crew aboard the ISS, trying to avoid debris. The officer shown on screen wears a MIR badge (in Cyrillic).
At around 19:45, as Teal'c is speaking to Jack and Sam, he briefly reacts to something or someone off-screen and cracks a smile, before quickly recovering. He then returns to his less animated expression.
While securing the three zones, Siler reports that zone one is secure, followed by Carter's similar report for zone three. After Carter's report, O'Neill is seen watching a blast door close, after which he reports that zone two is secure. There are only three zones, and the entire complex is already locked down; if zones one and three are already secured, zone two must also be (regardless of layout). Given that a blast door was still open after the first two reports, and considering that zone two only borders zone three, Carter's report was incorrect. (O'Neill should have called her on it, as he must have known.)
When Daniel comes into Jack's office, he knocks on the wall. The wall is concrete, yet we hear a knock on wood.
If the base's self-destruct sequence has been manually activated, it cannot be deactivated by computer alone; both of the keys must also be simultaneously turned off manually.
Major Kearney's rank insignia is wrong, It should be a brown colored oak leaf, not blue. Blue indicates Lt. Colonel.