There are several items you’re going to need to find in the many districts in Deathloop. These items are hidden all over the area, and you’re going to need to do some serious digging to find them. There’s a safe you can gain access to at The Complex, but you need to find a crank-wheel. You can find it somewhere, and it’s going to be well guarded.
The crank-wheel is a medium-sized item that you will need to carry with you to unlock a safe on Fristad Rock. Unfortunately, the crank-wheel is going to be hidden somewhere in Fia’s fortress. The best way to quickly locate the item is to go headfirst into the location and go through the entrance. How you enter the facility is up to you, but the best approach might be to dive straight through the middle and tackle all the Eternalists protecting it. You don’t want to sound the alarm, though.
Once you’re through the entrance, there’s going to be a large truck at the front, with two Eternalists standing outside of it. Take them out, and slip past the truck. A pathway beneath the truck will be on the other side, and in the middle will be the crank-wheel. All you have to do is grab it, and you’re good to take it without where you need to go on Fristad Rock. Unfortunately, you’ll need to carry it in your right hand, so you can only hold a handgun in your left to protect yourself.
The next step is to get the crank-wheel to The Complex district. The only way to do that is through the delivery system. You need to unlock the one with The Complex and Fristad Rock to use it and unlock the safe properly.