So, to the first point of my previous post - should you?
Indeed you should, but that doesn't mean it has to be you alone. In other words, having a dramatic coach or stage director work with you on staging is a great idea. However, it's important to develop a trust in yourself that will allow you come up with action that suits the character. This will also help ensure that you can still deliver vocally and musically. As with other parts of the audition, good preparation translates into confident performance. The more experience you have, the more you will trust your own instincts (particularly with arias where you have had the chance to sing the entire role on stage).
So, yes - stage it on your own, but also have people you trust critique and fine tune, just as you do with a voice teacher and coach.