PDR1 How does an inability to conduct the lesson lead to death. I grant you, if the pupil subsequently goes off and kills himself and it can be shown you taught him the wrong technique some lawyer may take a pot shot at you, but the teacher was with the pupil at the time of the accident. Unless the teacher told the pupil to do something dangerous this line of inquiry surely fails.
It seems unclear what happened plus any faulty manipulation of the throttle should not have lead to death. Stay clear of Switzerland