Popup window that completely covers embedded objects on quiz slide

I want to add a custom button to a quiz slide where if the user clicks it, it will display a popup window that contains information to help the user complete the question. I want the popup window to cover most of the slide, and completely cover the question and answer text.

However, I know that by default, the embedded objects (question and answers, etc.) on a quiz slide have priority, and that they will always be on top of the stack.

Is there a simple workaround to this issue?