Many of the safe codes in Prey are fairly easy to find, be it on sticky notes or hidden away close by. But one code in particular is a bit tougher to find mainly because you don't actually find the code until later in the game through a video. And this is to the first safe you find in the game! So here's the run down.
In the Neuromod Area, just after you pass through the testing labs, you'll find a safe in the debriefing room. We already gave you the code in our guide on Safe codes, but if you want to know where it is located, start by getting familiar with the room. The whiteboard is key because that is where the code used to be before someone erased it. Don't bother trying to decipher the erasure, as it won't help. No matter where you search you will not find it right away. That's because you will find it in Morgan Yu's office–your office–later in the game.
When you get to your office, you'll find a video recording of yourself and in the background left on the video, you will see the code on the writeboard before it was erased. The code is 5150, and if you take it back to the debriefing room and open the safe, you will get a handy chipset and some other useful items.
It's a bit convoluted and clever at the same time. And now you know.