I feel like it would've been a great moment for Erza's character if she really had delivered that blow to Eileen when she said, in Wendy's body, if Erza was capable of attacking a friend's body.
It would have shown that Erza was not fucking around and would sacrifice a friend for the sake of the guild, since this friend is basically dead, up until this point at least.
But no, it looks like Hiro hates fun, or portraying his characters the worst way possible.