It's almost like their bowing to the other before the fight to the death begins. Very nice shot! I always love when something happens and you're able to catch it in time. I sadly get some awesome things but by the time I get my console on, it's stopped doing whatever it was doing xD. It's all luck and chance but when you pull off the lucky shot, it makes it all worth it.
Well there are actually a few tricks you might not know about that will help you get those shots. TAI will freeze an NPC in place for example. You can use SGTM to either slow down or speed up time, allowing you to catch action in mid scene more easily. So "SGTM 0.1" is 10% of normal game speed. Nice slow motion. And return it to normal with "SGTM 1". But as with just about any console commands I've learned it's usually not worth saving the game after you've been messing around too much. Just revert to an earlier save and play that section again.
To learn a heap more about console commands you can go here [link](Skyrim)