Factual error: As Reddington sets up the blood transfer between himself and Ressler he inserts the intravenous line in Ressler's arm first and then in his own arm. This is a big NO NO! This way the remaining air inside the line gets into the recipient's body and could very well kill him. Judging the expert way he handles the set up he should know to first insert the IV in his own arm, let the line fill with blood and then insert the IV in Ressler's arm.
Factual error: Early in the episode, a detective knocks on the door and identifies himself as being from the Metropolitan DC Police Dept., and displays his badge. Apparently the prop department gave the actor the wrong badge, because the one he flashes is from the NYPD, not the DC Police.
Continuity mistake: Agent Keen breaks the train window and dives through the broken glass and cuts her face in two places as she pursues the young man. Her two cuts alternate throughout the following scenes on the train from dripping blood to barely scratches. That evening at home with her husband her face is practically clear and at Reddington's home later that evening her skin is perfect.
Continuity mistake: The BMW 5 Series equipped with the dirty bomb you see in the beginning of the show is one of the 'F10' type. The car that actually explodes is another car. Possibly an elder 5 Series 'E34', but not an 'F10'. Later in the episode you see the F10 again, but when the FBI agent starts the BMW, the interior of an 'E60' BMW 5 Series is shown.
Factual error: When Red goes to meet Zamani at the Lincoln memorial, he initially walks down the monument steps eastward, towards the reflecting pool in the direction of the Washington Monument and finds Zamani at the base of the steps. The map that is shown of his supposed location in front of the Lincoln Memorial when the FBI starts tracking him, isn't a map of the National Mall, nor the Lincoln Memorial. Later, when they are walking and he is "on the move, heading westbound", they are actually walking away from the Washington Monument, towards the Lincoln memorial, to the location where they had originally met (and discussed the Cherry Blossoms). Two seconds later, they are near 14th St, which is easily a 25 minute walk from the Lincoln Memorial.
Plot hole: At the end of this episode Red takes off his shirt revealing his burned back, which leaves us to think that he might be Elizabeth's dad. However, this particular mark should have been noticed and written down in Red's prisoner file when he was taken into custody the first time (Episode 1). In that case Elizabeth would already know that Red is burned and could have asked some questions about it.
Revealing mistake: In the shot of the assassins fleeing the scene of the bullet-ridden Range Rover in Shanghai, China, people are casually crossing the busy street in front of and behind the car. Nobody is looking at what just happened. Computer generated graphics were used to place the car and assassins motorcycles in the shot.
Factual error: The FBI logo on the projector screen is not the actual FBI logo. There are supposed to be 3 red stripes and 2 white stripes. There are supposed to only be 13 stars, 6 more have been added next to the scale. There are less than 46 leaves on what are supposed to be Laurel Leaf branches. [The differences can't be intentional, as "unauthorized use" of the FBI seal only applies where a situation might be construed to imply that the FBI approves its use, not the case in a fictional TV program.]
Factual error: The episode starts with a scene of a household in Koidu, Sierra Leone where a family is killed and boy taken. Mombasa is an island town on the coast of Kenya, not Sierra Leone. Mombasa wouldn't have a village or poachers or wild animals because it is an urban area. And Red later on reveals that the boy who was taken after the family was killed was actually Dembe, whom he found tied up in a brothel in Nairobi, which would again place them in Kenya, not Sierra Leone. Dembe would be an appropriate name for a person from Sierra Leone, not Mombasa.