As far as I know, the only way to close apps out, with or without VO is with the app switcher. If there were, I'm sure some of the more advanced iOS users would've told someone, or at least posted it to this site.
Hello Misty,
There is a way, but you need a jailbroken device, so unless you have done this, the short answer is no; you must go into the app switcher to do this. There is a JB tweek that would allow you to do this without entering the app switcher but apple does not allow it of course. Hope that this answers your question. -Andrew-
Comments
No, not that I know of
Closing apps