Its all plot she could have killed both of them 3 times now all she had to does is attack them whilst frozen but of course being a villain her motives have to be explained just buying the protagonist enough time to escape.
or if i decide to be an idiot like you people i could just say she decided to move sasuke cos she knew if she tried to move naruto he would've kicked her a$$.she could've moved either one of them but for some reason she moved sasuke,it could be because she knows naruto has badass sensing skills and would just find the place or whatever
ps:if you are going to use some stupid logic for your arguments,make sure it cant be used against you cos then the whole thing is not fun