In the "Slow" video: 2:06
We look at a page with names, rooms, roles and birthdays.
The birthdays are what we will focus on.
Ignoring the first two numbers, as they are the year, this leaves us with birthdays of 301 - 308.
As only 301 - 305 are translated, it gives us possible codes for the keybox.
0112, 0215, 1223, 0516, 0321.
Trying each code leads us to find that 0516 is the correct choice.

how do we know the code for first safe 0516 ? there was only one tip in that room .. a note in a locker on piece of paper saying "the code is my birthday", wasnt it?

In the "Quick" video: 2:38 - 3:27
After going upstairs with the code 3168.
Take the key to Room 305 (on a chair), use the Lobby Key to take a shortcut back to the starting area.
The old picture is in Room 305, in a draw. (Be sure to press Space after interacting)

someone know where the old picture is located?

Thanks for the feedback! I'll give it another try. LOL yeah I missed the message.

Either video will cover all achievements, 10 minutes and 4 minutes respectively.

After picking up the flashlight in room 216, (in small text for 4 seconds) it will say
[Q] Flashlight On/Off

It's very easy to miss.

What key do you use to turn on the flashlight? Didn't find anything in the menu. I would think it is F given it is the default in my FPS games. Also tried to activate it via the inventory.

Does it include all achievements?

Thanx

Thanx for the quick video guide.