Although the fourth panel always has the beat, usually a funny one, I like when I can pop a joke in the middle of a scene, too. This one is particularly good because Darkblade makes the joke, and he's not often the funny one. He's got a gruff exterior when he's not talking to the Crusader, so it's nice to crack that every once in a while.
It's also interesting how the scenes break. I always had Darkblade and Blurstreak having a kind of adversarial relationship, which fit the general Batman vibe. But then I hit on something in the panel that directly follows that which deepens that reasoning. It was something that was always there, and made a lot of sense, but it wasn't obvious to me.
Want to find out what it was? Well, you'll have to grab the book on Free Comic Book Day.