Still, let it be known the screenshot is right there for the viewing
And that has to be the DB armor, in the screenshot depicted
Here , 4 uniformed men attack 2 of the Emperors Blade guards (notice the similar armor types as those of the 2 Blades depicted in the demo videos, the 4 bolts one the center guard are a dead giveaway)
Obviously, 2 guards of the highest order of soldiers on the face of Tamriel would not be wasting there time chasing bandits in random caves, it has to be a scene from the initial attack by assassins on the emperor. And anybody who is going to pay money to see the most powerful man on Nirn and his family dead would not hire some 2 bit mercenaries to do it, Only the most professional and willing assassins can be implied
Besides, Concept art and finished product are almost never the same so the mismatch is to be expected.
My theory anyway