Automatically fail a Quiz if a critical question is failed

We have had a request from our School of Health Sciences. They run quizzes which contain questions in which an answer can result in 'a decision which is clinically unsafe'. In this case no matter how well the student has done in the other questions, they must fail the quiz.

We have some workarounds involving grade overrides in the gradebook but none of them provide the solution being requested. Our best option prevents students from seeing any of their question grades.

So we would like to request:

1. An option to mark any question as critical.
2. An automated overall Quiz grade of 0 if any critical question is graded 0.