Thank Q!
Theory:
What if the pics of the space shuttle and owl go together?
The space shuttles deployed many a satellite. What if one of them launched was a military satellite that is a keeping an eye on the pope.
The comment was only "guardian of the pope". Not destroyer of the pope. If that satellite kept an exact location of him at all times I'm sure there is something else that can take him out.
He can't stay in a bunker or dumb 24/7. Not to mention I wouldn't be surprised if there were white hats close enough to him to do the job if need be.