I like the Professor's idea of relaxing Music before and in the Background during training.
They did a study years ago with weight trainers and fitness trainers:
To get them to rev up,become more intense,to get them more determined and into the training they found Rock/Metal was the best.The Rock /Metal sort of just caused them to go faster,harder.
To get a more sustained,constant energy output, result they played more mellow music.
So music DOES Soothe the Beast.
also
If the training is one on one,Instructor and student ,once the student starts getting tense,or goes off the page ,STOP the Training,tell the student he is doing his own thing and not relaxing or paying attention to the training or drills.
That or when the student tenses,goes off the page and or speeds up or does their own thing,then in a one on one the Instructor can go off the page ,go faster,go harder and drive the student to ask to relax and slow it down.(show them what they are doing,by doing it to them)