I don't think you'll have much success doing this. Firstly, a submit by email initiates a whole bunch of asynchronous user interaction so you have now way to know when that is done. Also, while a document can close itself, it does not have the security priveledges to close the entire Acrobat program, so the window would remain, it's just the form would be gone.
Why can't you switch back to PowerPoint? You can't alt-tab back? Or simply close Acrobat by clicking the X?
Chris
Adobe Enterprise Developer Support