Mercedes Mason makes an uncredited appearance as Captain Zoe Andersen, giving a speech in a flashback video from Officers Nolan, Chen and West's Police Academy graduation. Captain Anderson was killed off at the end of S1,E16: "Greenlight".
Officer Nolan speaks of a time when he was a hostage during a bank robbery. While longtime Nathan Fillion fans remember the fourth season of Castle, the episode "Cops and Robbers," where Castle (Nathan Filion) is held hostage on a bank with his mother, the bank robbery reference is the pilot episode of "The Rookie". John Nolan goes to his local bank and is caught up in a bank robbery. His experience was the character's "lightbulb moment" that resulted in the construction worker changing cities and careers toward becoming a police officer.