Ah, that makes more sense. Though in some cases (e.g. Outlier) links do kind of need a full screen presentation to be usable.
There does't seem to be a way for us to tap into the volume buttons when we're presenting an overlay view like Screen Reader, because the main app still has control over those. (if anybody finds another app that's somehow managed to pull that off, let us know and we'll try to figure out how they did it)