Other mistake: When the hallucinated Jonas is leading Dr. Kieran upstairs, a red light can be seen glowing on his hip where his Beretta is holstered. It looks as if Corin Nemec is carrying an Intar (a training weapon with a glowing red crystal in the grip) prop instead of a normal pistol. Can't be due to a hallucination - Dr. Kieran couldn't hallucinate a Goa'uld training weapon he'd never seen.
Add timeGrumpy Scot
Revealing mistake: In the scene when the timer exceeds 38 minutes, said timer is displayed in big digits on a computer screen. There is a shot of General Hammond with the Stargate in the background. There is a pane of glass between the General and the Stargate. In the shot, General Hammond turns and looks at the gate, and then the camera's focus changes from the General to the Stargate itself. In doing so, a reflection of the timer in the pane of glass is also brought into focus. However the timer is displayed correctly when it should be flipped left to right as all text is when it is reflected in either a pane of glass or a mirror.