Brian - it's difficult to see in that clip where the actual breakup begins.
In this clip it's a bit clearer, starting at about 1:40.
The 144 is in a dive an pulling serious G's to recover when the left wing fails (some say the canard fails first). But the angle of attack is much more modest than 80 deg immediately prior to the breakup. It's a G loading issue rather than a stall.