Considering the show's premise, it shouldn't come as much of a surprise that the characters on "Blue Bloods" usually end up having to face the consequences of their own mistakes. The series revolves around a family of law enforcement officials in New York City, and follows them as they face the kind of difficult dilemmas and cases that usually lead to them initially making the wrong decisions and assumptions. Additionally, to its credit, "Blue Bloods" has never been afraid of showcasing and confronting the flaws of its characters. That's always been true for its central ensemble as well as its supporting characters, including Detective Maria Baez (Marisa Ramirez).
Introduced in the show's third season (via IMDb) as Danny Reagan's (Donnie Wahlberg) new partner, Baez has faced plenty of unforeseen obstacles during her time on "Blue Bloods," and like all of the series' characters, she has made some notable mistakes along the way. However, it's a decision Baez makes early on in Episode 9 of "Blue Bloods" Season 12, titled "Firewall," that is arguably her biggest in the show's history.
The Season 12 episode of "Blue Bloods" sees Danny Reagan and Maria Baez stop a man on the sidewalk after a woman tells them he'd been following and harassing her. Danny and Baez question the man about the allegation, but he feigns ignorance and causes a scene, telling a crowd of onlookers that the detectives are harassing him without cause. At the same time, the police department's system is crippled by a cyberattack, which makes it impossible for Danny and Baez to check the man's ID.
Feeling increased pressure from the crowd, Baez opts to let the man go. Unfortunately for her, it's eventually discovered that the man is wanted for an assault and is a suspect in five other, similar cases. Later in the episode, when Danny and Baez are alerted about the man's possible whereabouts, they follow him into an apartment where they find its tenant tied to a chair and their suspect gone. To make matters worse, Baez is ultimately shot by the man when she and Danny finally manage to catch up with him, and she ends up in the hospital as a result.
All in all, Maria's decision in "Firewall" not only puts another innocent woman in danger, but also gets her in trouble with her superiors and puts her on the wrong end of a shotgun blast. Unsurprisingly, the weight of Baez's mistake in "Firewall" wasn't lost on fans of the show.