The cannon room had the same sort of annoying action direction this series has suffered from the beginning: After Edo-Erza appaered, Natsu and Gray did absolutely nothing but scream with their mouths hanging open. They didn't kick the king's ass, nor did they annihilate the soldiers readjusting the cannon back to its original target. Nor did they help their Erza to defeat Edo-Erza. Really useful mages!

Wendy should have roared the foolish cat mob away. There's only so much martyrdom one should accept before giving up and finding another way to get through.