Stop slide audio on clicking Submit in quiz

Hello again. I'm using the lastest version of Captivate 12. My desired behavior on a quiz slide is that the when the learner selects an option the slide audio stops immediately. I cannot seem to make that happen in this version, despite creating an interaction that stops Media if Question.AnswerChoice variable is "not empty". If I can't make that behavior happen, I'd settle for the slide audio stopping when the user clicks the Submit button, but it continues to play until they press Y or click anywhere, which I do not want.

Any idea how to make the slide audio stop as soon as an answer is selected, OR when the Submit button is clicked? I could do this easily in Captivate Classic...but I know, preaching to the choir. 

Thank you!