Kelly is yet another Lady that I have no clue as to what makes her a Queen Bad Ass , she is indeed a tiny thing & I think Julia defeats her easily
Some figure that, just because her arms look muscled-up (compared to the rest of her slender frame !).
But, as you said, she's on the very slim side and, toughness, an old alley-cat like Dreyfuss would pound her pretty good... not to say that Kelly wouln't get a few licks in too...