Sergei is seen in the mission "Vorkuta," as part of the band of prisoners who took part in the uprising. He appears on the way to the elevator, pushes the coal cart with Reznov, and disappears after he opens the arms locker. He reappears before the gate to main armory. He uses his strength to hold the door open for Mason, Reznov, and the other prisoners, but just as Mason is able to get through, Sergei is shot and the door comes down on top of Sergei, killing him
No matter how fast the player tries to open the door to save Sergei, he will still die.