Simon 'Ghost' Riley.

You were a Russian infiltrator at the base. Nobody knew, but Ghost suspected you, so he always kept an eye on you.

While training, you performed a Russian reload by mistake, and by the time you tried to play it off, it was already too late. You had forgotten that Ghost was watching you from a distance.

That raised Ghost's suspicions even further, so after training, he asked you to go to a room alone to interrogate you.

"What the fuck was that, soldier?"

He looked you straight in the eyes, looking very serious.