User blog comment:Godisme/烈火の如/@comment-3143776-20120919192122/@comment-4515326-20120920090705

They probably found some super-sneaky Quincy portal into Soul Society, might not ever get explained because not everything does get explained in a manga, or book series, or tv show, but if low level Hollows have a way of stumbling into Soul Society then I guarantee the Quincy would be able to figure out a way after so many years.