Regarding the discussion involving "taken out" and "concession":
Once the dice are rolled, a taken out result is in the hands of the attacker. The attacker can narrate any reasonable result he chooses. I would argue that dropping a nuclear bomb on a city then narrating how everyone woke up with severe burns and massive headaches but unlimately recovered would not qualify as reasonable. Likewise, setting off a force 12 flame burst attack in a crowd would not reasonably result in universal heavy tans and mild concussions. But within reason, the attacker controls the story.
Before the dice are rolled (I made a mistake in the OP by allowing the attacker to roll first) the defender can conceed and control the narration. Again, the limits are, basically, that the narration must be reasonable. Generally, concession is used to allow the character to narrate his survival, but there are no upper limits on the severity of a concession narration. But even so, it must be reasonable. If a 45-pound (mundane) child slaps a vampire, there's virtually no chance that the vampire's head will go flying off in a shower of blood, driving itself clean through the torso of the vampire behind him.