So I've been thinking about Reichenbach... and unreliable narrators.
If you haven't seen both seasons of Sherlock, don't read this, I pray you. If you're jonesing because of season 3 in production, you may be interested. 8)
John is usually our eyes in Sherlock. But not always. Particularly in season 2, where we get scenes without John at all, often from Sherlock's point of view.
In Reichenbach, not only do we get that, but there are parts where our eyes -- we the audience -- are the only eyes. We've gone omniscient, where you can float over the scene without a fixed character who anchors us.
Like with the snipers. Before John gets to Baker Street, we get to see that Mrs Hudson's sniper is there. While Lestrade is on the phone, first we get to see him -- presumably from his sniper's point of view -- and then we switch around and get to see the sniper himself.
Finally, we get to see John's sniper at Bart's. John certainly doesn't see him, but we see the man arrive, set up, and wait. The sniper is indoors, so it's not Sherlock seeing him either.
When John stands up after the fall, we've become the sniper, looking through his cross hairs. Aiming down at John.
It could be Sherlock imagining this, except that officially Sherlock is not part of the scene by that point. And right then John doesn't know about the sniper as far as we know.
(Personally, I now think that John had two snipers. We see the one at Bart's, who arrives before John does; John probably had another who tailed him from Bart's to Baker Street.)
Now, the point of unreliable narrators is that you cannot trust 'em. The problem here is that WE are the narrators for the snipers. This isn't John or Sherlock.
Maybe that's reassuring to you. Maybe not. What it does mean is that the snipers were real and that the danger to Sherlock's friends was real.
Me, I'm wondering how much of the magic trick was more complicated than it appeared. 8D More thoughts later.