When Carter is in the plasma chamber, the first 2 times the graphs are shown the Blood Oxygen level is on the right hand side of the screen, after Nathan tells Carter he has to breathe in the plasma the Blood Oxygen level graph is now on the left side of the display.
When Carter and Henry are in the Cafe at the end, Carter mentions the sequence where Henry uses the memory device on him, but, Henry wasn't one of the 'G3' group, so he could not have transmitted the memory in a dream.
Near the beginning of the scene when Fargo is about to be hit by a truck, in one brief scene, you can see him positioned to be tackled by Carter for the stunt maneuver.
But, when the sequence is rerun in the dream it is shown from an angle behind Fargo and it can clearly be seen that he is still crouching to call the dog back to him.
The experiment at the center of the episode was supposed to have been conducted on people who worked, and therefore slept, regular hours. But Sheriff Carter was effected by it. It seems very unlikely that the Sheriff, whose duties would include responding to emergencies at all hours, and conducting extended investigations, would work a set schedule. In fact, as this episode shows, the Sheriff often conducts investigations late into the night.
When Allison tells Stark to turn off the machine in Kevins room. He says "No", but Allison was standing right there when he turned it on, if she really wanted it turned off she could very easily have just gone over to it and turned it off herself. Why make her seem incapable of turning off a simple device, she is at this point the head of GD and has a very high IQ. Turning off the machine should be easy for her to do.