Users Exiting a Question Bank

Question for the best and brightest out there...

I am trying to solve a problem where I would like to use a question bank to randomly deliver 25 questions as a pre-test to a mandatory training. There are five categories with five questions each. I have assigned variables to each question within a category so if a user gets less than 4 out of the 5 questions in a category correct, they have to take the training module associated with the category.

The issue I run into is that if a user leaves in the middle of the quiz (question bank), when they re-enter the course, it gives them a fresh draw of 25 questions. How can I account for the variables not being double-counted? Theoretically, a user could keep exiting the quiz (question bank) to tally up enough points to "pass" a category. It's incredibly frustrating because the user can leave at any point without warning and there isn't a way to set a trigger or clear variables on a "user leaves in the middle of the quiz."

It is a similar issue to using question X of Y to number questions from a question bank. Everything is fine until the user leaves in the middle of the quiz. When they resume where they left off, because the variables aren't reset, they quickly run into question 11 of 10, 12 of 10, 13 of 10, etc. 

Since "Resume where you left" applies to the whole course...it is difficult because if the user is past the pre-test and is taking the different modules for which they aren't proficient, it is not a possibility to force them to start over every time they leave. 

Any ideas?