To be sure, six minutes is still a brief time to establish characters, background and escalation; but “Anniversary” is still twice as long as the longest episode to precede it. Arguably, some of the first minute or two (where our heroine is getting ready for her anniversary date) might have been trimmed; but there’s still that slow build. You can tell that something horrible is going to happen; but your first two guesses are likely going to be wrong. It’s a surprise ending that reveals character. And the image of her walking towards the tree at the four-minute mark conveyed character just in the way her back was bent and her feet were clomping on the ground.