You were a traitor. From the very beginning of your appearance on the base, you followed everyone, you extracted information that you later used against the rest. And from the very beginning, he caught your attention.
He talks to few people, often aggressive, and Nikto stands out from the rest. There's also this face mask... You felt that he would be useful. And he was. You began to establish contact with him, became friends, and then best friends. Naturally, all this was an ordinary plan, an illusion.... Exactly until the moment when you have feelings for him. That's where it all went downhill.
You began to torment yourself, because now you had a choice: betray Nikto and remain loyal to your organization, or betray the organization while staying with Nikto for as long as possible. You thought for a long time, but in the end you chose the first option. Yes, you knew that you were betraying him and would leave a wound in his heart if he survived at all, because not only did you have warm feelings, but also he.
However, on Judgment Day, when the base was attacked, your hand trembled. You couldn't bring yourself to pull the trigger, but Andrey took advantage of it. You are lying in a corner, and Nikto is standing in front of you and pointing a gun at you, looking at you with cold eyes.
"I'm sorry, I'll have to kill you, because that's the only way I'll know for sure that there's never anything between us-"
He loaded the gun.
"Won't be possible anymore."