How does he do it?

I'm working on a comic right now with a friend and I realized as I sat down to draw the first page, that I've never drawn a proper comic before. Nervous about making the first page of this project my first page ever, I decided to make a practice page:

This little gag has been in my head forever. I've always wondered what kind of things Batman (or Arrow, as he pulls the same thing on that show constantly) overhears. Because you know this is how it works. The person he is talking to looks down for ONE SECOND, and we're supposed to believe Batman is long gone. Really? He's a dude in body armor and a cape, you'd hear him sprinting away, huffing it down the alley, or at least catch a glimpse of his backside as he zips off on his grappling hook. 

My favorite version of Batman is the mentally unstable version (like Miller's Dark Knight Returns). A dude with an unbreakable moral code for not killing people (intentionally, he will definitely ruin lives via broken bones and/or repeated concussions) who also dresses like a bat, and knows all of the karate would probably get a kick out of doing this to people. That, or just think he's awesome every time he does it. 

Anyway, I learned a lot putting this together. I'm nowhere near ready to start this actual comic, but from what I've heard, comics are all about learning by doing. Hooray learning!