Well if she’s asking you in any way to ‘empty your mind’ you’re in the wrong place. What does she mean by “calming the mind”......and ‘Why is she teaches certain yoga ‘breathing’ techniques....are questions you could ask.....her answers would reveal much.
What they mean is stay in the moment. Focus on your poses and getting your alignment right for the pose. Don’t let outer thoughts or worries creep in during your practice. The breathing is just to stay oxygenated because some people tend to hold their breath or do shallow breathing when struggling with the poses.