When a psychologist's number comes up, Reese must protect her from one of her patients while eluding capture by the FBI, who are closing in fast. Meanwhile, Finch receives an unwelcome visit from an old acquaintance.
A firewall is a piece of hardware or software that controls what data can move into or out of a computer system. It is designed to provide protection to a network or single computer against data from sources that cannot be trusted, notably the internet. It is these firewalls that hackers must get around to enter complex systems. The name derives from construction firewalls designed to keep fires out of buildings, and has become a metaphor for the mechanisms we use to protect ourselves from others.
The box around Caroline Turing is yellow, indicating her awareness of the existence of the Machine.
The episode began on May 17, 2012 and just after Donnelly escorted Carter into the NYPD Real Time Crime Center which had Reese and Root on a large monitor showing footage that occurred two hours before, then flashes back to two days earlier, where the action begins.
There are certain similarities between this episode and "Pilot":
Both episodes start with a flashback and end with Reese looking into a security camera. Moreover, the camera used by Reese to contact The Machine in this episode is the same location as that used at the end of "Pilot".
The person of interest in both episodes is female and thought to be the victim. As it turned out, both women were actually the perpetrator.
Also, both episodes involved the POI hiring HR, except they were hired anonymously in this case, and Turing put the hit on herself while Diane Hansen ordered the deaths of other victims.
The date on Reese's phone shows May 17 although following to the overall timeline in the episode, the hotel escape happens on May 18.
Zoe's clothes change color: at 5:30AM, when she calls Reese to tell him that she was going back to Turing's office, she's wearing a black dress and a white coat. A few minutes later, when she checks Turing's laptop and finds out that she's truly Root, she's wearing a red dress and a black coat.
This NYPD Officer has a "CIB" collar pin. CIB stands for Combat Infantry Badge and is issued by any branch of United States Armed Services. NYPD are allowed to wear military ribbons and CIB on their uniforms
With Reese in the backseat Carter and Fusco drive by a huge billboard for the movie "Think Like A Man" which had Taraji P. Henson in a starring role.