Leon looked slightly distant when she started talking, as though remembering something that had happened long ago, then...he reacted to the cultist, who Akurin had alerted him to, by shooting it in the head twice, essentially ending the sudden confrontation and probably scaring her even more. When he turned to her, however, he DID notice the paleness and the shaking and the near-sickness.

"...I know it's not easy. My first time doing that was against an innocent person who'd been infected and made into a mindless shadow of what they once were. It doesn't get any easier, but there's a way to help yourself deal with it..." He brushed an errant hair out of Akurin's face, looking her in the eyes. "...remember that if you didn't do that, didn't incapacitate them, then they would be very likely to hurt or even kill you."

Leon set his hand on her cheek, hoping to help her feel just a bit better about what was going on. He knew how bad it was. He'd been through it. He'd just taught himself not to think of it.