I'm confident that the Kneecaps option would cost us Tolerance. Dark as some Magical Girl genre anime could get, we're still the Unknown Rival. Unknown we may be, but we're still the Rival. We're here to out-perform the Main Character, or act as a foil that enhances both Main Rival and Main Character throughout the series.
Shooting the Kneecaps just to prove a point, and not to mention handicapping the Main Character, well, that makes us more of a Nemesis than anything else really. At least from my perspective.
Edit:
Also really, if we were gonna shoot her in the kneecaps, we should have just gone and done it from the start instead of trying to be smug about it. That screams Fake-Smug and Insecurity to me, and I don't want our in-quest audience thinking the same.