You might be able to make a correlation between getting stuck in the deep half guard and being thrown into the deep half of the pool, without your swimmies, by your asshole cousin. It's that feeling that rushes over you when you know something imminently bad will happen, the same way Samuel L. knew he would eventually get eaten by a shark. The deep half is a powerful tool that has been around for many years, and over the past few it's popularity and variations have grown exponentially. That's great and all for offense, but how the hell do you defend it without having to rely solely on good balance and opportunity to remove yourself from the situation? Well you can escape it in almost magical fashion - Chris Angel style.
Let me just say this technique is awesome, I remember the first time I saw something similar, about 4 years ago, and I can remember my jaw drop when I played a clip of a Japanese BJJ player seamlessly roll to his opponent back. Several years later I see this great tutorial brought to us by our buddies at MMA Outlet and TriForce Japan. It's only now that I can fully appreciate the beauty and simplicity of this counter. In some ways it's very berimbola, but that shouldn't make you shy away from it's effectiveness. So next time that 300lb white belt decides he wants to give you the good old Jeff Glover, throw your swimmies on, roll to his back, and choke that fatty out. Remember kids, wait at least an hour after eating before you enter the pool.