Once again, you are on your own for this one, fighting all the enemies on this level.
As warned, do NOT use any of Tycho's terminals, or you'll be teleported out into space... only for a short bit, but it does displace you from your position on the map.
You have two main goals in this map: to activate the `bridge' across the plasma in the western half of the map, which can be done by hitting the various switches found in this room, and then, once that is completed, hitting a switch near the base of the bridge that will open up the eastern side of the map. Then, you need to head to the eastern side of the map, and to activate the switch in the hallways surrounding the plasma pool, which opens the doors to the exit term at the far south of the map (near your starting point).
Be warned: near the hallway that contains the switch you need to get into the eastern side with, there is a platform that will drop you into a deep pit of plasma, from which you can't get out of. (Specifically, this is located at the north end of that hallway). Don't risk this death, instead, use the path afforded to you by the bridge in order to get to the switch.
Exiting this level takes you to Hang Brain (15)
In the room with the bridge that you erect from switches, there is a switch that is partially below the plasma level. You can tag this switch yourself or with weapons, then head for the west elevator shaft (which actually doesn't have an elevator). When you get there, the floor will have dropped down, and you can drop into this, head south to avoid falling into a pool of plasma, and follow the passage to a big blue Hunter, and a star shaped switch. Kill the alien and tag the switch to open a ammo cache, a 3x powerup, and a teleporter back.