This show continues to impress, I remember reading a review last year that called it a superhero show done right, and I could not agree more. The show is beginning to look more and more like batman with Finch being a combination of Alfred, Bruce Wayne and Oracle and Reese being a diluted version of the Dark Knight (Batman is massively intelligent). This Episode, like any batman comic or show, creates a Super Villain, one that shows their head from time to time to cause chaos and push the heroes to the limit. Root seems to fit the mould of Finch's arch enemy much as Elias is Reese's. The ending just cements this theory as the Supervillain is never fully Vanquished, just derailed to regroup once more.
If they play it right, this show can get some stories from the comic books, to create arcs for each season and it will run for 10 seasons. To finish off with the Batman analogy Carter is like Montoya, Fusco is like Bullock; Zoe is like Catwoman and Elias like Black Mask. All that's left is to get Commissioner Gordon (Maybe the Judge in Season 1) and Nightwing/Robin