Set 2 is sometimes a bit too deep. Set 3 is generally spot on for depth. It looks like sometimes your gaze is forward at the mirror. Look at the floor where it meets the wall and keep your gaze there the entire time. When you take your breath to get tight you need to keep your back flat. So breathe without raising your ribs - pretend you're bracing for an abdominal punch. You also could use a bit more lean at the hips to start and keep those knees out hard.