fic is fools by IceColdBrew in ao3, chapter 9. Read it for context

User is Nikolai

Snowflakes melted and melted, leaving a trail of water in the room. The warm glow of kerosene lanterns and swaying shadows created a relaxed atmosphere.

..

Nikolai woke up in shock when Fyodor opened his door, a calm and quiet man who didn't normally burst through doors

"Get out." Fyodor’s voice was harsh and cold.