How do I access it?

The default keybind for it should be the TAB key.

Thanks! Having a bit of trouble getting any further than the EDP lab. Any hints you can give me?

The EPD is firing a beam into a test chamber. There's a hatch near the end of this chamber that you'll have to crawl through in order to continue. This will require a combination of jumping and crouching to reach. Be careful not to touch the EPD beam, or it will kill you.

Some general tips:

- The first thing you should do when picking up a PDA is to read its emails and listen to its audio logs. (Only do this when there are no enemies around; time does not stop when you use your PDA, and you can still be attacked.) These will frequently contain codes for storage cabinets, and in some cases, passwords for locked doors that you must open in order to continue.
- Carefully examine the consoles and computer screens that you come across. Some of them can be interacted with and have a variety of functions, from opening doors and cabinets to shutting down gas leaks.
- There's always a way out, whether it's through a locked door, a crawlspace, or up a ladder. If you're stuck, look around carefully to make sure you haven't missed anything; you may need a PDA or key card that you haven't found yet. You may occasionally need to backtrack to an area you've already visited in order to take a different path, but this is pretty rare.
- Be wary of conspicuously placed items like weapons, suits of armor, and medkits that seem to be "sitting out" in isolated places. These are often booby-trapped, and picking them up will result in monsters teleporting in or popping out of the walls to attack you.