Meruin spotted Mutt and saw his intent. From the match she had seen earlier, Mutt could move at insane speeds, and she figured she had less than a second to react. Rather than test out her barriers against his strength (she really didn't like the odds) she simply dissolved the barriers and used winds spell to push her a bit to the side, at the same time chanting for another spell.

As soon as Mutt pounced, he would sail straight through the air and go passed the spot Meruin had just been at.