Is there a way to randomly select a scene?

There's no trigger for jumping to a random scene. 

Here's an option that might work: 

• Put the first part of each scenario on a question slide in a Question Bank (QB). 
• Insert a draw from the QB that randomly picks one slide. 
• Adjust the QB slides so they jump to the appropriate scene to continue the scenario. 

Here are some User Guide entries that might help: 

• https://community.articulate.com/series/articulate-storyline-360/articles/articulate-storyline-360-user-guide-how-to-use-question-banks 
• https://community.articulate.com/series/articulate-storyline-360/articles/articulate-storyline-360-user-guide-how-to-choose-feedback-and-branching-options