Deluded Mind

I just started this game and already have a question. I am at the part where I need to find a 4 digit code to open a admin. door. I believe you have to
find 4 numbers around the area and put those into the keypad. First of all I only seem to be able to find 3 numbers. I went on U-tube and watched 2 different segments and it seemed as if each game had different numbers to enter. Does anyone know if the game has different numbers for this code?
If so any suggestions on how to find the numbers I need would be appreciated. I also have viewed any documents I have found and read all of these
several times now. One is of a drawing and I thought maybe the pictures there are a clue. Any help appreciated.

I found a written walkthrough here. The walkthrough is in Dutch, but I ran it through Google Translate. Perhaps this walkthrough will help you.

Thank you so much for the link. This will really help me.

I am glad that I was able to find it for you.