Modify variables managed by storyline

Good morning

Not having succeeded in resolving my problem and without a response I deleted the slides and went back on another track. But to explain my problem and in case other people are interested, I will make a lighter file including the method and its failure. To quickly summarize the problem, I have a file with random questions and some of these questions have a follow-up.

For example, can we use this material with a yes no question, the correct answer being no, we continue with the question why? and this is where the situation becomes complicated. the question why is outside the random question and we are redirected to it but once the explanation of why is given when we return to the rest of the random questions we get stuck.

The solution that I eventually found is to make these two questions mandatory but in the event of a wrong answer (yes) the question why no longer has to be.

The file will arrive a little later I have to do it.

THANKS