This guide based solely on personal experience. If anyone is willing to do research and fact check this, please do so.
Congratulations! You've just made your way through the time consuming Light Containment Zone and dangerous Heavy Containment Zone, only to wind up here. But if you have time to read this guide, you're either in god mode or are not actually playing the game right now. Standing still is gonna get you killed in this game. This zone's danger levels depend on how the game's been going for everyone else. If the SCPs are constantly getting lost in Heavy (Containment Zone) and not a lot of people have died yet, you should be golden so long as you have a good keycard and sense of direction. This guide is to help with the latter.
I'm only doing the Entrance Zone because the Light Containment Zone has the numbers and letters above the doors to help you (the meaning of which can be found on the wiki) and the Heavy Containment Zone has no landmarks that I have found to be useful to help determine where you are going.
Okay, so maybe not just navigation. This is for beginner's eyes only (as the rest of you already know this).
Guards can basically be considered the first wave of the blue armored MTF that spawn on the surface and they in fact look like said MTF as well, the only difference being their armor being white. The guards, however, have quite different loudouts, spawning with a Guard keycard instead of an MTF one and having a different gun. These guys first spawn in the Entrance Zone, but because of how they work you'll more likely see them in Light Containment Zone than anywhere else. You'd better be a Scientist or they'll either fill you with bullet holes or handcuff you and make you turn into an MTF instead of a Chaos Insurgent when you escape. However, their disarmer has limited range. Not that this matters, though, they'll easily fill you with lead before you can escape. (Sorry for bluntness) Oh and by the way, Disarmers don't work on SCPs.
Dead ends, obviously.
(Notice how in the last one, you can see a workshop on the left. If you have a Weapon Manager Tablet (MTF and Guards spawn with them) you can modify your weapons there)
This hallway. If you go through it , be ready for a dead end.
The intercom corner. I don't know what it is with this, but it seems to always have a dead end on the other side.
This office room is extremely helpful even if you're trying to go deeper into the facility instead of escape. It is very commonly located at least somewhat near a checkpoint and contains lockers that contain useful things.
In these lockers I found a radio and an MTF Commander Keycard, which can open the exits. (When playing as D Class, aim for Gate A. When playing as Scientist, aim for Gate B)
Never go left unless absolutely necessary.