Branching to content based on pre-assessment results

I think the easiest way to branch in that situation is to use separate Continue buttons on the Failure and Success layers of the pre-test Results slide. (This assumes you hide the NEXT button on the Results slide.)

• On the Failure layer, a Continue button would have a trigger to jump to section 3.
• On the Success layer, a Continue button would have a trigger to jump to whatever slide you want to end the course with. (Or it could just have an Exit button.) 

It is also possible to use one button (either a custom Continue button or the built-in Next button) to jump to different slides based on the user's score. 

The scores for the first Results slide you add to a course are Results.ScorePercent and Results.ScorePoints. In your case,  Results.ScorePercent needs to to equal 100% for the user to be able to skip section 3.

• One trigger would jump to section 3 with the condition that Results.ScorePercent < 100.
• Another trigger would jump to the end slide with the condition that Results.ScorePercent = 100.

Here's more info about variables and conditions:

https://community.articulate.com/series/articulate-storyline-360/articles/articulate-storyline-360-user-guide-how-to-work-with-triggers#conditions

https://community.articulate.com/series/articulate-storyline-360/articles/articulate-storyline-360-user-guide-how-to-work-with-variables