Nolan and Harper are assigned by Sgt. Grey to escort four juvenile delinquents to a prison facility in the Juvenile Immersion Program promoted by the city. While driving to the facility, one youngster is sent back to the correctional facility after robbing the police car. Nolan, Harper, Deputy Sharp and the three juvenile delinquents meet Warden Miller that brings two dangerous prisoners to expose the life in prison for the youths. Out of the blue, there is a riot in the prison and the group is trapped inside without any weapon. Meanwhile, Sgt. Grey summons Lopez and tells that LAPD has hired a tech company to use an algorithm to target officers who are most likely to be sued and she was flagged as the most problematic officer in the station. Therefore, West and she would spend the day with the nerd Elvis Grimaldi to show the police work by the book in quiet areas of LA and help him to collect data.
"Under the Gun" is another great episode of "The Rookie", with two great storylines. Why Nolan leaves the car key in the ignition of the police car with the juvenile delinquents inside is the great question and hard to understand. The segment with Lopez, West and the nerd Elvis Grimaldi is highly entertaining and breaks the tension of Nolan and Harper in the prison. My vote is nine.
Title (Brazil): "Encurralados" ("Trapped")