Safe Cracker is an achievement/trophy in the Metro: Last LightDLC, Chronicles Pack, awarded for opening all 8 safe boxes on the Pavel level. Each safe is locked and requires a key, usually found nearby, to open. All 8 must be opened in one playthrough of the level. Below is a written guide for finding all 8 safes and their accompanying keys.
Key 1: After dealing with the first guard, open the door and collect the knife on the table. Kill the other guard and go down the corridor. There will be a table to the left (just before opening the next door) with a few rolled up maps, a candle and the key on it.
Safe 1: Turn around, back towards the torture chamber. The safe is set into the wall just above where you picked up the knife .
Key 2: Upon leaving the torture chamber and entering this area, stick to the right and blow out the lantern to pass through the crawlspace. A lone bandit patrols this area. At the end is an item box containg the key.
Safe 2: This is found in the storage area infront of metal gate. Heavy guards patrol nearby.
Key 3: In the middle of the main area of the shooting gallery, on the ground floor, opposite the safe, there are a stack of crates and boxes to the right. Walk behind them (between boxes and the wall) to see the key hanging on the crate.
Safe 3: The safe is sat on some crates under the stairs, opposite where the key is found.
Key 4: After opening the doors by removing the throwing knife from the panel, head upstairs. In the control room of the shooting gallery, the key is in a red openable box on the wall.
Safe 4: Found upstairs, directly across from the key; follow the catwalks to the room with whirring machinery. The safe is on a desk by the door to the next area.
Key 5: After dealing with the men cooking around the fire, enter the shack on the right. It is hanging from a pan handle on the shelves in front of you.
Safe 5: Found to the left, after dealing with the men around the fire, there are a series of steps and planks that allow you onto the roofs of the shacks. Go to the end, and the safe is in the last shack.
Key 6: After passing the island with the generator and lights on it, there will be a bridge leading onto the next island. As soon as you cross this, it is in the shack on your right, on a shelf inside.
Safe 6: Across the small bridge to the right of the exit door, guarded by a bandit with a VSV, is the safe.
Key 7: After opening the door that leads out of the housing area, there will be some concrete steps leading down into the flooded lower level. On the wall is another red box you can open to reveal the key.
Safe 7: Exiting from the large flooded room, there is a tripwire grenade trap; disarm it and use the panel to the right to restore power to the corridor. This will cause the metal bars to a small room to open. The safe is inside, on top of a fridge. When you enter the room, the door will close behind you. However, it will open after a few seconds, allowing you to leave.
Key 8: Upon entering the next area through the pressure door after the previous safe, there will be a door into the main room to your left. On your right, there is a collapsed staircase; the key is hanging on the banister.
Safe 8: After dealing with all the heavily armed bandits, you will have to push a door open to exit the large room into a brightly lit passage. The last safe is on the left, on the floor.
Most of the time, once you leave an area, you can return to it as long as you explore. The first seven safes can be opened in any order. Only once you reach the room with the senior bandit cursing out the other bandits, is the door permanently closed behind you.
You can return to the room where you pick up the knife from the shooting gallery by following a passage to the left as you reach it.
You can return to the shooting gallery area from the shanty by following the tunnel back.
You can also return by taking the room past the big red button in the gallery, into a maze of tunnels, and exploring past areas with hallucinogenic mushrooms. Past a tripwire will be a hall with two guards and several prisoners, leading to a door to the shanty that is normally locked from the other side.
Finally, you can cause those guards to open that door by alerting guards on the other side (the pair near the radio, plus the one near the final safe, appear to work).
All keys are generic, you could use key 1 to open safe 8 and vice versa
Most safes contain some form of ammunition, Military Grade or otherwise. Aside from the very end, in the non-hostile section of Venice, the MGRs have no use as currency, so feel free to fire them.
In that section of Venice, the only things that you can spend MGRs on are at an ammunition vendor (pointless, since there is no more combat), the sex shows, alcohol, the fortune teller and Yanek, Pavel's informant.