Character mistake: 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 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.
Suggested correction: That amount of air would probably not cause any problem. It actually takes quite a lot of air to cause any issue.
Continuity mistake: In the first episode, Liz says that the fire happened when she was 14. Later in the series, she states that it happened when she was 4.
Suggested correction: Liz tells the criminal Reddington she got her scar at age 14. She could have been lying. Would you tell a criminal the truth in interrogation? Maybe she was testing his knowledge of when it happened.
Mr. Gregory Devry (No. 95) - S3-E11
Other mistake: After arresting the Reddington impostor, Ressler states that while hunting Red they had only one photo with a "passing resemblance to the man we've been working with." In S1E1 you can however see a high quality picture of Red on the front desk screen while he is arrested. (00:32:25)
Suggested correction: The photo that's seen on the front desk screen is the same photo on Reddington's wanted poster, which has been seen a number of times in the show. That is the 1 photo the FBI have that has a "passing resemblance" to Reddington today, which is what Ressler is referring to.
Other mistake: Elizabeth picks up a stuffed bunny which supposedly was from her childhood. The bunny has burns on it after being in a fire. You can see 2 plastic tag fasteners attached to the bunny, which wouldn't have survived the fire.
Suggested correction: Later we see in the flashback that Liz was holding the bunny. It only got singed as she was escaping. It wasn't "in" the fire.
