Use the following trick to get out of level boundary in the Cairo Green house. Enter the green house and take care of whatever is in your way. There will be a Aero Security bot, which is quite a tough opponent at this stage. When you get to the intersection early on, go left. Then, do not go up the stairs. Instead, get a explosive crate and throw it to the door near you on the same level. Shoot the crate to destroy the door, or simply throw a concussion grenade at it. Go in. Note: If it is still not open, do what you did before again. Instead of destroying the "generator", go on the small hill. preferably the one which is easier to climb. Jump on the pipe above without a plank on it using the climbing ability (hold Y) then jump onto the one with the plank, as it is now reachable. Repeat this pattern until you get to the wall which has the door in it which you came through. You should be very near the top. Jump across the wall. Be careful, as you will land on apparently the same pipe you jumped from, just on the other half of it (which you are not meant to know about). If you jump off, you will fall and die, even if you have level 3 Silent Moving which makes falling less damaging. You will be able to see the entire level from here, which gives you a very nice advantage if you do not have the Seeing Eye biomod.
Note: After you lift the mag rail containment chamber after placing the box in the way of the door, when you enter to kill the scientist instead of trying to kill him. throw a gas grenade. This causes him to run out and deactivate the door. Therefore, whether or not you get locked in, you can get out without worrying about the door. He then runs out and cowers in the nearest corner of the lab. Kill him, get praised by the Order, and take the mag rail.
Georges Martin.