Having trouble marking questions as completed

Hi

I have a quiz launch page with links to the four available questions on it. They are optional questions so although I want the learner to view feedback, I don't feel that they have to take every question. Here's how I would like the quiz to work:

1. Link 1 on slide 2.5 opens slide 2.6 as a lightbox. 

2. User answers question, and clicks submit button on slide (submit in player skin doesn't appear to work for lightbox)

3. User is shown feedback, and when clicks OK lightbox closes and the link on slide 2.5 has a check next to it.

I have found that creating a variable for the question which is set to true when submit is clicked doesn't work with lightbox slides, so I ditched the lightbox idea, and tried this with "jump to" actions from the links on slide 2.5 and then from the question slides back to slide 2.5

I can get the questions to mark as complete on slide 2.5, my problem is that I can't get feedback to show before the slide jumps, so the learner has no idea whether they were right or wrong.

I'm attaching a screenshot of slide 2.5 and of a question's set up to see if anyone has any idea what I should do...

I hope this makes sense!

Laura