Surprising, yet inevitable

First of all, I didn't make up this term.  I got it off the writingexcuses podcast (an excellent podcast, by the way).  But it's one of my favorite things about reading.
Basically, this is when the ending is so surprising that it takes a minute for you to realize that it was always going to happen.  That it was obvious.
For example...
WARNING!  IF YOU READ THE MANGA BLACK BUTLER (Kuroshitsuji) AND HAVEN'T READ CHAPTER 57 DON'T READ THIS!!!
In this chapter Ciel (13 year old main character), Lizzy (fiance in an arranged marriage; very cute) and Sebastian (Ciel's demonic butler--literally) are all fighting these zombies.  To make matters worse, these Shirigami (like Japanese grim reapers) drop down and start fighting Sebastian. Ciel's boot gets stuck in part of the ship's floor, and Lizzy's surrounded by zombies.  Ciel grabs a gun and starts shooting the zombies, but runs out of ammo.  That's when Lizzy turns toward him and says, "I wanted you to think of me as cute until the end," as she smiles sadly.  Ciel yells her name, and the page goes all black except for a few white blood splatters.
The next page shows her kicking butt with the sword she took out of the wall behind her.
To begin with, everything was in place for this scene.  We already knew that her mom was a knight, that she was more worried about Ciel thinking she was cute than anything else, and that the shirigami could kill Sebastian if their blades went through him.  So, remembering that Lizzy was always only cute, I was positive she was dead.  I was upset.  I was mad.  Now Ciel was alone again!  That's not fair!  So when it cut to her kicking butt, I couldn't believe it.
It all makes perfect sense now, in hindsight.  Of course she'd know how to defend herself, her mom being a knight and all.  And of course she wouldn't want to show Ciel she could take care of herself, she wanted him to think she was a cute girl he could take care of.  But she'd rather save him than be thought of as cute.  All these pieces were in place about a billion chapters ago.  But I never saw that ending coming.
I guess my point is that one of my favorite techniques is this "surprising...yet inevitable".  Also, I still can't get over that whole scene, so I decided to blog about it.