She still has to notice anything wrong about his fighting style, mostly because Rydia is still struggling with the weird feeling of being drained at the use of her magic (and she can't even joke with Rosa about biting Kain and use osmose to restore her mana- not only she's not so close with the white mage anymore but, well, since he turned holy dragoon he definitely started using his magic essence...) and the whole thing with the eidolons... the summoner isn't really looking at Kain so much, her instinct is what drives her while fighting at his side. Just give her time to realize he's basically asking enemies to hurt him, she will definitely start to worry. A lot.

"Well, this old lady can help too, you know?"

No potions needed, she will tend to her wound later in a good old fashioned way if nothing else decides it'd be fun to attack them, the adrenaline is already alleviating the pain by itself.

"It's just..." Another fireball is thrown at another group of creatures, that's... definitely easier to handle than the ice blocks midair, even if the summoner can't really tell why for now. Maybe the whole place is aligned with a specific element? "... magic isn't so easy here." And- let's admit it, there's no fun in the battlefield when all you do is blasting enemies with fire. But shh...