William already knew all of that, and yet he still used and triggered this attack. What she missed was that the lightning arcs didn't come from all over this monster's body, not in the same way Ibra got hit with.
William kept flashing around, hitting the monster three times with each dash. In each and every single time, he made sure to target the same spot over and over again.
So, when he released his lightning, they came like exploding from a grenade or something, rising up to the air from a single point, augmenting the damage this monster took.
*Crack!* And then his sword came in, added the last touch in the middle of such a scary attack, cracking open this layer of shell.
William didn't just want to crack this shell, nor did he randomly select it.