Slumdog Millionaire's Hidden Slap

Anyone who knows me knows that I love action movies. I love em'. Spy Kids, Mulan, Harry Potter, you name it, I love it. In order to celebrate the awesomeness of action, I decided to look into some classic action-sequence editing techniques. 

But then, I started watching Slumdog Millionaire instead. And just as I was watching, I saw a flash! It was then that the fate of this post changed forever.  The first scene of Boyle and Tandan's Slumdog Millionaire required a transition the lead character to transition from a live television stage to a small torture chamber. Here's a short clip of the scene:

As you may have noticed, Jamal entered the torture chamber utilizing an advanced transition called the "fist train". At first glance, we see this--

However,  my friend, (who is a boy), noticed something flash through the frame mere milliseconds before the cut.  "What?" I asked serenely. My (boy) friend jerked his head away from the screen to meet my gaze. "I just saw a hand."

TO BE CONTINUED... 

...HERE:

While I thought him crazy at first, upon further investigation I found Canon's claim valid. 

Here's the frame-by-frame of the transition:

...That's a hand alright. Someone on the crew got to be the guy who smacks Dev Patel. As eerie and ridiculous as it sounds, the offstage slap actually makes some sense. Cutting between static and moving shots often prove jarring to the viewer. While practically unnoticeable the naked eye, the quick movement of the slap smooths out the seam in the transition. The moral of the story is, when in doubt, slap your actors.