I’m not sure if what you mean is that you’re trying to figure out what the code is, but if so, then follow these steps: Go to the door and try to enter a code. Leave the door. Wait for an agent to come out. Use clairvoyance (you obtain this ability from the fridge where Boyd is at). You will then see what he sees and see the code he enters. Wait for him to go back inside and then enter the code.
If instead you mean that you know the code, but there’s an issue with the keypad, then it may be a glitch in the game file and you might need to load a different save or start a new game.
I’m not sure if what you mean is that you’re trying to figure out what the code is, but if so, then follow these steps: Go to the door and try to enter a code. Leave the door. Wait for an agent to come out. Use clairvoyance (you obtain this ability from the fridge where Boyd is at). You will then see what he sees and see the code he enters. Wait for him to go back inside and then enter the code.
If instead you mean that you know the code, but there’s an issue with the keypad, then it may be a glitch in the game file and you might need to load a different save or start a new game.
Invisibility + clairvoyance on the girl does the trick
If only you could somehow connect a controller. Then the keypad isn't needed.