It will, unless you are on Easy.
actually not... potions do not help getting your head back on your body or against an angry sword going through your body searching for the light on the other side...
That`s not it. The point is you are dead the moment the Finisher activates, not if you`ve actually been killed yet or not.
It reminds me a bit of Dragon Age when someone fires an arrow at you the game has already decided whether or not the arrow will hit. If the game decides the arrow will hit, there`s nothing you can do to avoid it. Dodge and the arrow will hit, dive and the arrow will hit- Even jump behind a brick wall before the arrow reaches you and it will still hit.