"Brat, why are you holding back? Did you think that if you don't use your full power then you can survive against me for 1 minute?"
Fion6 asks Allen. It was only 30 seconds but as you can see Allen was already pretty injured and even after using the spiritual Tiger he wasn't able to do anything.
On the other hand, Fiona already felt that Allen was holding back. So she told Allen to use his full power. If he really thought that by not using his full power he could survive against her, then he was wrong.
Even though Fiona surpassed her strength, the thing was that she wasn't even serious while fighting him.
