Shortly after the intro when Jeffords is talking with Peralta about whether or not he went to the hospital, Jeffords says "Your tone is braggy but your words are real sad." Behind him, an cop is walking with a perp towards Jeffords. Two lines of dialogue later when Jeffords asks if the hospital cleared Peralta for active duty, the same cop and the same perp are walking in the exact same direction.
Jake laughs off a doctor's diagnosis of his internal bleeding, stating that, "That's where the blood's supposed to be." In Unsolvable (2014) a year earlier, Jake discussed a convict's injuries following a jailhouse beat down, including internal bleeding and was fully aware of what that meant.
Captain Holt wears his Commendation breast bar above his World Trade Center Breast Bar. When the WTC bar is worn, it is worn above all other medals but below the American Flag bar.