I would recommend that you spend some time planting landmines near two entrances to this control room. You can find them by the red lights shining above them [#237]. Place one or two landmines near each entrance or even further back into the control room, especially since you'll be allowed to recollect them if they won't blow up during the course of the upcoming battle.
You may now find the stairs and proceed to the upper room. Find a new computer terminal and use it to lift lockdown to this section of the facility. Make sure that you're standing near one of the windows [#238] and wait for enemy troops to show up. The first wave should be killed by the landmines, so it'll be up to you to deal with the rest. Prevent enemy units from leaving your line of fire and you should be fine.
You may now proceed to the area where you've started exploring this control room. Collect new items and proceed to one of two available passageways. It doesn't really matter which one it's going to be, because eventually you'll get to a small room guarded by enemy units [#239]. Kill them and proceed to a new exit.
You should be able to reach laboratories very soon. Go to the left room and step through a destroyed glass wall. Now you must go to the stairs. Head down [#240], but watch out for a room to your right - enemy units may be stationed there and it'll be up to you to kill them. Throw a couple of grenades, enter that room and deal with the rest yourself.
You'll soon find out that you'll have to gain access to the fourth sector before you'll be allowed to continue your main assignment. Exit the laboratory and spend some time exploring the area. You should be able to find an opened hatch nearby [#241]. Head down and explore the tunnels in order to find a new document titled Supplement notes. You may also go to the second laboratory through one of the windows. You'll find a CD inside - Cancellation.
You don't have to explore the second laboratory thoroughly, because you'll return there later on. Proceed to the main corridor of the lab complex. Keep going straight and once you've reached a large oval room turn right. Just as before, you must be on a look out for a hatch leading to an underground passageway [#242]. Use the ladder and go forward.
You should be able to reach a new ladder in just a few seconds. Use the ladder to get to a secured room. Once inside, take your time to find a large control panel on the wall [#243]. Approach the panel and press the action key to use it. You may also take ammunition and medical supplies. Exit this room (through the door - not the tunnel).