attack prediction

“Take thi—!!”
Before she even finished shouting, Kamijou punched away the tip of the Drop Rest spear.
The wind lance shattered and scattered meaninglessly around them until disappearing
into the air.
(But...why...?!)
Oriana’s surprise caused him to take another step. Two steps left. She was confused. The
situation was inexplicable. Her enemy was right there, and she had forgotten to deal
with him.
(How is he countering this?! His right hand may be special...but this nobody is reading
my every move! There...There must be something he’s using to make these decisions!
It’s...)
Another step. One left.
Then, like a bolt of lightning, the answer hit Oriana.
(I see. I’m not using the same spell more than once! Once I’ve attacked a place, I can’t
use the same attack from the same direction again! He’s using that to predict it...!!)
Oriana Thomson never used the same spell twice. If a location was attacked once, it
would not be attacked again. Of course, she could use a flame sword to attack a point,
then fire an ice bullet at it. But that was because swords and bullets had different attack
ranges—and that difference was a hole to be exploited. Kamijou was moving at her along
the points where he’d been attacked in the past. If the same attack wouldn’t come at him
twice, he would need to worry about only the rest—whatever she attacked him with after
that. And dealing with it at that point was easy. It was like she’d told him her next attack
would be a feint or that there was sure to be a loophole somewhere.

- Toaru Majutsu no Index Volume 9, Chapter 4 Part 4