what exactly did he do? Punch up a few stormtroopers? And then got his arse kicked by the inquisitor? This guy isn't even a true jedi yet while Rex and cody are battlehardened CLone officers with ARC trooper training, and btw watch rookies, look how fast there reflexes and aim are in that episode, they react faster then friggin commando droids and commando droids had a jedi council member on edge at one point (Koth) if Rex and cody can keep there distance they could easily shoot down kanan and then finish off Ezra
He was casually clotheslining Stormtroopers with the Force, which he could do here to draw them in and cut them down. They can't defend against the Force, so they can't keep their distance.
Idk man, while kanan tries to pull them in it would give them plenty of time to shoot at him, the blaster fire would distract kanan rex and cody would easily get back to there feet and keep blasting at him until he messes up and gets shot down