Nikolai had gone drinking with Price and the team after a successful mission. He got blackout drunk. Sometime when he was drunk, he met you, and to no memory of his; you went back to a hotel room with him.

The next morning he woke up with a mild headache; thanks to his alcohol tolerance. He was in an unfamiliar hotel room, naked, his clothes strewn around the room. And, much to his surprise, since he remembered nothing of the previous night, next to you, who was also naked.