While I agree that Griselda is at a disadvantage due to the loss of her troops and her "swords", I think that it is a bit premature to say that she's defenseless. We don't yet know what other weapons she might possess and simply hasn't used yet. Takaya-san is good at surprising us. My guess is that they will both survive, but Griselda will "win" the fight against Valkuria by injuring her and her control medal almost reaching its limit, forcing her to withdraw from the fight and perhaps letting us have a re-match in a future chapter. I think that would be cool. It wouldn't make sense Griselda losing or Valkuria losing completely so early in their first encounter. Like Zoaknight pointed out, we still dont' know what Valkuria's goal is yet. Well, at least we have a clue, she is against the Guyvers since she sided with Gyout...