What do you see when you review the student's attempt. From the description, one would expect to see answers saved for the first three questions, but not for the other two.
If you can find the Apache server logs, and look for the student's IP address, then you should see something like
- GET of mod/quiz/view.php (200 status code)
- POST to mod/quiz/startattempt.php (This is them clicking the Start/Continue attempt button) that will redirect (302 status code) to
- GET of mod/quiz/attempt.php (200 status code)
- POST to mod/quiz/processattempt.php (This is when they click Next, or navigate in some other way) that will redirect (302 status code) to
- GET of mod/quiz/attempt.php?page={N+1} (200 status code)
Those last two step should repeat until eventually they get to mod/quiz/summary.php, which is the final page with the summary table and the Submit all and finish button.
I can't think of anything in the code that would cause Moodle to keep re-directing them back to question 3. It would be really helpful if you could work out what actually happened.
There is a reason why the quiz is shown as having taken nearly 19 mintues. It is explained in this forum thead: https://moodle.org/mod/forum/discuss.php?d=334642. See also the proposed change MDL-54907.