Have auto-advance ignore validation rules

Hi!
I have a page with 20 math questions on it. Here's what I'd like:

1. Validation such that you can't submit the page unless you got all 20 questions right.


2. I set this up with custom validation, no problem.


3. Everyone auto-advances to the next page after 5 minutes, whether or not you've finished all 20 Q's and/or have some errors that haven't been fixed.


4. Here's where I run into the error.

The auto-advance feature is attempting to move on after 5 minutes but when there are blanks/errors, the validation-based error warning is triggered & the whole page restarts the 5-minute timer.
Anyone know how to get auto-advance to ignore validation rules?