I don’t think you can have an action doing nothing, it should either throw an error or it won’t be added to the page at all. An On: Show action on page level is run once when the page is loaded, so it cannot be used to do something on the page later on. It can be used to show the object when a user returns to the page.
Your conditions and use of the variables should be correct, you just need another trigger. Add a second action to each of your audios
On: Done Playing
Target: Your object
… and use the same conditions (if “audio1 = 1 AND …)