The shaft Carter escapes through and later uses to re-enter the Stargate complex has no security, not even a padlock.
Dr. Fraiser holds up a syringe with yellow sedative. After Dr. Fraiser injects Carter with the sedative, you can clearly see the syringe full of the yellow fluid.
When Maybourne stands up as he is leaving the café near NID Headquarters, he puts his cap on twice.
After Teal'c wakes up in the infirmary, after he attempted to escape, Dr. Fraiser tells him that, while he was "delirious", he injured several guards, giving a few of them concussions. However Teal'c did more than just injure the guards; he killed one of them when he shot a guard twice with a Zat gun.
"Dr Fraiser" was an alien.
"Dr Fraiser" was an alien.
When Colonel O'Neill takes "Dr. Fraiser's" sidearm and points it at Major Carter, he fails to take it out of its holster. While holstered, the pistol's trigger would not be accessible.
When Maybourne gets out of the car (supposedly in Washington DC) a Vancouver trolley bus is visible in the background.
When Teal'c is in the infirmary and knocks out the guard, you can see the "unconscious" man lift his legs onto the gurney to be wheeled away.
If Maybourne is not an alien and agreed that Carter was hallucinating from chemical exposure, why would he agree to fly her from Washington DC back to Colorado for medical treatment when there were military or civilian medical facilities close by? They would have had to pass the hospital at Andrews Air Force Base to get to the plane.