That being said, there is one missed opportunity here: Why wouldn't the cadets give Ezra up? Of all the students outside of Ezra, only two befriend him, and both agree the Empire can't be trusted. One uncovers Ezra's deception, but since he was there to investigate the Empire himself, they join forces. Meanwhile, the second cadet legitimately wants to be a Stormtrooper, but switches sides following a very brief conversation with Ezra. Rebels had room for a more complex take where Ezra trusted both students, only for one to turn against him and impress his Imperial headmasters.
Instead, the lesson learned is "Stormtroopers who never take their helmets off are evil". No seriously, every other cadet is constantly wearing a mask, presumably to make you forget that Stormtroopers are human beings. You know, because then we might feel bad about all the murders the Rebels committed in the past five episodes alone. That's not to say every episode should be morally complex, but "Breaking Ranks" could have gone in this direction and been a little better for it.
Regardless, the rest of the episode works so well, it doesn't take away from anything. Beyond the aforementioned walker fight sequence, Kanan and Hera squeeze in a tightly directed TIE Fighter battle that doesn't take away from Ezra's scenes. Also, having Ezra round a corner only to walk right into his old enemy Kallus was a great touch, adding to the feel that he's in danger at every moment. And even though the Inquisitor only arrives once the shooting stops, he's still a terrifying villain, teasing horrible things are on the way with a few subtle lines. I suspect only Vader himself would be more imposing at this point, and even then not by a huge margin.
If I could ask for one more thing, it's that this caliber of episode be used to showcase other members of the Ghost's crew (especially Sabine, who's had very little screen time). I'm sure we'll get there eventually, but almost every episode has focused on Ezra and his force abilities. It would be nice to show there's more to Star Wars than being a Jedi-in-training. But we're still moving in a great direction.
Bottom Line: "Breaking Ranks" continues to raise the bar for Rebels, this time taking a look at the faces behind Stormtrooper helmets. While it misses a chance to explore why good people become evil Stormtroopers, the episodes still hits every good note and makes for a fantastic watch.
Recommendation: What, you're not watching this series already? You should, this is Rebels at its best.