1. Ready for a fight then head through this door.
2. Continue up these stairs.
3. Go down these stairs in the neighboring room. Fight past those guards through the gate up ahead.
4. Access this computer to update your mission goals. Note the health on the left and the armor on the right.
5. Piotr is in cell block A. You can continue to block C or B, but if you choose B you'll get a large medkit.
6. You'll find the medkit here on the right.
7. The door on the left leads to blocks C, then D and A. Instead, climb the stairs ahead for a more direct route to block A.
8. Fight your way around this corner to the A block cells up ahead.
9. Here's the cell you want - A24. Open the door to initiate a cutscene.
10. Piotr has been transferred to cell XB2 for punishment. You're told to look in zone 12.
11. Descend the stairs on the right before continuing through the gate on the left.
12. Grab the medkit on the right then pass through this door.
13. Head downstairs and fight your way past the guards. Ouch.
14. This is the corridor you want.
15. Open this door to initiate a cutscene.
16. You've found Piotr -- time to make a break for it.
17. Yippee an escort mission. Backtrack through that door on the left.
18. Ascend these stairs. Piotr will only follow you if you choose the right direction.
19. Fight your way to these train tracks. Grab the medium medkit on the right.
20. Descend to the lower level. Small temblors rock the cavern.
21. This explosion causes a small cave-in, blocking the tunnel ahead.
22. Backtrack here and another explosion opens up this tunnel.
23. Snipe the guards ahead.
24. Use the switch on the right to call an elevator above.
25. Activate the elevator switch to ride it down and end the level.