While at the fundraiser, Ressler condemns Dembe for drinking a beer on the job. It later becomes known that Dembe is a devout Muslim and therefore abstains from alcohol.
During the meeting between Agent Keen and Floriana Campo the camera is pointed alternatively at one or the other. When the camera is pointed at Floriana Campo, it is clearly raining; when is pointed at Agent Keen, though, it isn't (and the shoulders of her coat are dry).
The bad guy falls and breaks his leg. Ressler survives the same fall unscathed.
A tracheotomy would not help someone suffering from a barbiturate overdose. Tracheotomies are used when a person's trachea (windpipe) is swollen shut, like in the case of a severe allergic reaction. A barbiturate overdose interferes with the central nervous system's ability to function, which prevents the lungs from functioning, so further opening her airway wouldn't help any.
As soon as Reddington insisted on giving answers beyond "yes" or "no," the polygraph would have become invalid and the examiner would have had to stop the test. In any event, the FBI would never have put Reddington to a lie detector, knowing that polygraphs are useless on psychopathic subjects.
The derailing train is a passenger train. The overhead shots on the news show a freight train.
The that the waiter accepts in Montreal is clearly a U.S. banknote rather than Canadian. Anyone who thinks that this is possible has never tried to offer American currency in Quebec.
The FBI raid the restaurant when they believe that Red is escaping. But the restaurant is in Montreal, and the FBI have no jurisdiction. They would have had to work with the Canadian authorities.
The cover of the Ukrainian passport has a major issue in that, instead of the Cyrillic character for P, it shows a Latin character for N (essentially spelling "Nasnort" instead of "Pasport").
During the overhead shot of the ship the FBI held Red on, the ship can be seen to be flying an Australian flag rather than an American one.
At 00:45 -the closed captioning reads: "Please to meet you" but the lyrics written by The Rolling Stones are: "Pleased to meet you".
The FBI is not above torturing a suspect in order to gain information.
Ressler attempts to shoot an unarmed man in the back. That is attempted murder but it is never mentioned.
It is never explained: just how did Red get his hands on a newspaper and scissors in order to cut out an article.
Jamming a pen into the throat of a person who is not breathing because they've overdosed is, surprise, wasted effort.
Thank goodness Tom is a man and will, therefore, never notice that the carpeting has been replaced.