It might be a bit of a risk, but he had to understand how this new threat spread before he could effectively fight it. To that end, he took note of the shadow cast upon Cornelia's Knightmare by his own, and used that Shadow to render her Knightmare invisible, where his own factsphere could freely view Cornelia being attacked within her own Knightmare by an entity she could not see or touch. The more information he held, the easier it would be to combat it.

And if in the process it put Cornelia into a position of vulnerability… Well, he was hardly the kind to say no if opportunity smiled upon him for once instead of frowning.

"Get away from me!" it looked like she screaming from lip reading, necessary because her external microphone was switched off. All the Stand seemed to do was pin her back by the neck to stare in her face while she struggled in vain, and then let her go. Her body went slack, ceased struggling although her face took on monumental levels of simultaneous rage and surprise all at once. "You - You devil! Taking me here of all places!"

He zoomed in on her face, and took note of a peculiar set of rings forming around the iris in both her eyes. Lelouch fully expected another faceless Stand to manifest around Cornelia, but none arose. Strange. He had assumed - Unless there was another step to the infection? But what could it be?

-Lulu's Bizarre Rebellion Chapter 26