After closing the door on John and Snow in the secure room, Kara shoots the palm scanner, presumably to disable the lock. Unfortunately for Kara, all this would do is prevent that palm scanner from being used.
The beginning shows a recap of Prisoner's Dilemma (2013) during which Kara is shown injecting John with the sedative. The original scene showed her beginning to push the plunger and then saying, "Hey, lover. Did you miss me?" This scene shows her saying the line first and then injecting him.
The scene referenced contains a goof. In the original scene, Kara depresses the plunger, says the line, and then presses the plunger a second time. The recap here only shows the dialog and second plunger press, leaving out the first.
The scene referenced contains a goof. In the original scene, Kara depresses the plunger, says the line, and then presses the plunger a second time. The recap here only shows the dialog and second plunger press, leaving out the first.
At the climax of the episode, Kara activated the bomb vests John and Snow were wearing. Snow's vest is shown to have a 5 minute time. The events depicted after this point would have taken longer than 5 minutes though (descending from the 21st floor of one building, going to another building, and gaining access to the roof, to name a few).