Sogiita tried to approach Ollerus in order to drive some guts into the gutless man before him.
That was when Ollerus showed the true value of his own power.
Simply put, it was an unexplainable phenomenon.
Even Sogiita who received the attack couldn't even slightly understand what had happened to him.
Before he realized it, he had been blown away a great distance. His entire body, from the surface to his very core, had received damage equally. The shock didn't just come from one spot and spread from there; it was more like an unnatural force had permeated his entire body like a cloth being dunked in water.

Toaru Majutsu no Index SS vol.2 ch.21