"If-Then-Else" is the eleventh episode of the fourth season of the Person of Interest television series. It originally aired on January 6, 2015, on CBS. It is the seventy-ninth overall episode for the series.
"If-Then-Else" was written by Denise Thé and directed by Chris Fisher. The episode continues the series' long-running Samaritan storyline. It centers on the Machine evaluating a list of possible strategies to allow the team to succeed in a mission to recover New York City's stock market after Samaritan attacks the stock exchange and cripples the city's financial system.
According to Nielsen Media Research, the episode was watched by 10.08 million viewers with a 1.7/5 ratings share in the 18 to 49 age demographic upon airing. The episode was highly acclaimed by critics and audiences alike, with reviewers praising the originality and execution of the premise, the thematic value, and the shocking ending, with many calling it one of the series' best episodes.
Plot
Following the events of "The Cold War," Samaritan cripples New York City's financial system after attacking the stock exchange. Amidst the turmoil of the plummeting stocks, Finch (Michael Emerson), "Root" (Amy Acker), Reese (Jim Caviezel) and Fusco (Kevin Chapman) head to the New York stock exchange to revitalize it. Decima Technologies operatives ambush the team, prompting them to take cover inside an office break room. Meanwhile, Shaw (Sarah Shahi) is in a subway train spying on a man with access to the stock exchange's security codes. Matters are complicated when a suicidal man unveils a bomb vest he threatens to detonate. Root consults the Machine for help, and the Machine in turn evaluates the possible strategies to help them succeed.
The episode periodically flashes back to 2003, where Finch is in a park playing chess with the Machine and using the games as analogies to various concepts he teaches it. Several games later, as the Machine is appearing triumphant on many occasions, Finch tells it that he doesn't enjoy chess since it was created during a time of cynicism and societal imbalance. Finch believes people should not be assigned "values" and sacrificed; those who treat life as game of chess deserve to lose.
In the present day, the Machine uses its knowledge of chess as a basis to narrow down its options and run simulations. In the first, Finch and Root go to the security room, while Fusco and Reese take over elevator controls. This results in Decima forces overpowering both teams and killing Finch. The second option swaps the destinations of the two groups, which ends up with a wounded Reese detonating a grenade, killing himself and everyone in the security room, while Root professes her love to Shaw before dying. Both of these scenarios also show Shaw shooting the suicidal bomber and being immediately arrested by SWAT teams.
In the last simulation shown, the whole group non-violently takes over the security room and stabilizes the market while Shaw talks the suicidal man out of bombing the train. Left with little time, the Machine deploys this option even though it only has a 2.07% chance of the team's survival in taking over the elevator. These odds increase to 22.48% when Shaw arrives with explosives to fend off the attackers. The elevator, however, stops functioning right as they are about to escape. Shaw decides to sacrifice her safety and leave the elevator to press an override button on the other side of the hallway, passionately kissing a concerned Root to distract her before shutting the elevator door behind her. But before she can return to the elevator, Martine (Cara Buono) catches up and shoots Shaw multiple times as the elevator doors close, while Root and the team watch in horror.
Production
"If-Then-Else" was written by longtime Person of Interest writer Denise Thé and directed by Chris Fisher, also a veteran crew member. This is Thé's tenth episode written for the series and Fisher's eleventh directing credit.
The episode's narrative structure is significantly different from other episodes in that the majority of the episode is made of simulations, by the Machine, of various scenarios resulting in different outcomes. The execution of this tactic was praised by several commentators due to its opportunity to include humor and more outlandish elements than what is typically allowed. Series showrunner Greg Plageman also voiced his initial skepticism over the idea until he realized the value of it, and went forth with it.