Hi Justin!
If you slide is using a seekbar you can make it so it is 'read only' in the player settings under player controls. You can also set custom players settings for an individual slide by double clicking the slide in the slide layers panel and then choosing 'Custom for selected slide' for the player features option.
If you aren't using a seekbar you might be able to get away with placing a rectangle over the slide that the audio is on, and turning the rectangles transparency to 100% blocking the user from being able to interact with the audio object. The rectangle will need to be the same length on the timeline as the audio.
