I'm looking at this, and just... WTF. Revolvers don't do this. Revolvers *can't* do this. You'd have to release the trigger at least nearly completely, in order for the cylinder rotating mechanism to catch, then pull the trigger again, which takes quite a bit of force since you're rotating the cylinder as well as cocking the hammer. After looking more closely, I was thinking, perhaps his alternate hand got caught up in the hammer, pulled it back which rotated the cylinder, then released it, allowing it to discharge. Most modern pistols have internal safeties that prevent this sort of behavior, which you have to disable if you want to speed fire. After rewatching it a number of times, it doesn't look like he caught the hammer to me. On top of that the muzzle flash for that 2nd shot doesn't appear to be coming from the actual muzzle. I'm not sure WTF is going on here.