Here we are on the final chapter of the game, Lara is seeking the Iris witch is now in the custody of Verner Von Croy. How did he get out of that cave with the Iris and why is Lara stealing the Iris from her mentor? Naturally this item is heavily guarded by all sorts of soldiers and advanced security systems. You also have the assistance of a computer hacker named Zip who will guide you through the levels. Listen to Zip, then proceed down the hall to the left. Shoot vent cover in laser-sight mode with your HK in first mode. Take the large medkit, then crawl through the vent to watch a cut-scene that plays. Continue to the end of the shaft, then turn right staying down to avoid a laser that's moving above. Get a large medkit then turn around, approach the hole in the bottom of the shaft. Lasers protect this opening so watch the laser moving overhead. When it goes away, quickly stand then jump over the hole. Continue forward to the safe spot. Go through the vent on the right, then do a forward flip to the dark room. Search the shelves to get a small medkit, a Hammer and some ammo for your HK. Climb back through the vent, then shoot the next vent cover with your laser-sight in first mode. Flip forward into the new tunnel then immediately duck to avoid the moving lasers. Turn left then wait for the laser to move behind. Now stand up then make a run for the opening at the end of the passage. Crawl around the corner, then go through the hatch to get another Rose. Now retrace your route back to the beginning of the level. Security lasers are now protecting the hall, watch their movement and learn the pattern. When the top lasers start to move away from you, run after it then quickly jump over the bottom lasers that are approaching. Crawl to the end of the passage, wait for the top laser to come and go then stand and climb the wall ladder leading up to the next vent. Move forward until a cut-scene plays showing you the Iris. Follow the passage to the end then collect some more ammo for the HK. Walk down the next passage to keep quiet. After a brief cut-scene showing the huge guard below, approach the gate then shoot the lock with your laser-sight in first mode. The duct will break, then you will slide down to the room with the guard. Aim for his head in first mode with your laser-sight equipped. Now shoot him, when he turns around immediately shoot him in the head. Return to the duct then drop through the opening to the floor below. Go through the duct with the loud explosions, but try not to get burned. Pick up a small medkit at the end then climb the wall ladder to the room above. You are now in a tall room with a ladder and another security laser moving back and forth. Before climbing the ladder, pull up into the alcove to get some more HK ammo. Drop down then go to the front of the ladder. Time your climb to avoid contact by sticking to the right side of the ladder, start your climb as the laser moves off to the left. Turn left then shoot the shaft cover in first mode with your laser-sight equipped. Climb into it then go left to get more HK ammo. Continue to the end of the vent, making sure to walk. You should be able to spot a guard without being seen, a quick headshot in first mode using your laser-sight will silence him. Flip forward to the hall below, big red beams block your path so target the damaged vent cover in first mode with your laser-sight equipped. Crawl through until you can stand, then draw your HK in first mode with your laser-sight equipped. Destroy the vent then exit to the hall. Listen to Zip who gives you a clue about the sleeping guard ahead. Keep quiet as you walk around the glass wall while getting the High Level Access Card from the desk. Use this card to enter the nearby supply room behind the guard. A quick search of the shelves will get you a small medkit and some HK ammo. Return to the main passage, then walk to the elevator and press the button to open the door. Enter then use the panel to reach the next floor. Two guards can be seen talking to the right as you exit. Crawl toward the triangular door to the left then use your new access card to enter the room. Here are two lab technicians inside who won't bother you if you don't bother them. Locate the button on the central table, then press it to watch a hologram of the Iris. Quietly leave this room. Those guards are still talking by the crates, shoot them in first mode with your laser-sight equipped. You must kill the right one then the left one. Walk to the end of the hall, then stop at the corner leading to the right. Peek around the corner and wait for the guard to walk away, a quick headshot in first mode using your scope will silence him. Continue toward the Iris which can be seen through the metal cage. Head through the door on the other side of the room and ignore the man in the radiation suit, he just works here. Press the switch to the far left to release a radiation suit from its compartment. You aren't after the suit, but rather the Access Code Disc that drops out with the suit. Take the disc then return back to the elevator. Return to the main floor then walk to the sleeping guard and turn right. The red beams are now gone, walk down the passage to the computer terminal and use the disc to open the vent. Climb into the hatch, then locate the pole on the right. Watch and learn the sequence of the explosions that runs from the top to the bottom of the shaft. Slide down the shaft to the middle then backflip into the gap to get another Rose. Safely drop to the bottom of the shaft, then crawl through the low opening until you reach a walkway overlooking a large room. Below, is a door being guarded by one of those armored troopers. After hearing Zip, move quietly across the walkway until you reach a hall leading to a room with some shelves. Search the shelves for a small medkit and a Cloth. Head to the next walkway, then quietly make your way down to the floor below. Locate the door on the far right then walk over to it. Use the access card to get inside, search the two closets to get some Chloroform that you can combine with the cloth and also a large medkit. Open the second closet to get more Chloroform and a small medkit. One of the glass tanks holding the insects, burst open and you need to leave this room quickly. Walk up to the trooper, when you are behind him use the Chloroform-soaked cloth to put him to sleep. Now use the access card to open the door, then enter the next room. Follow the passage until the door slams shut behind you and a trooper charges from the door ahead. Quickly target in laser-sight mode, then take him out with a headshot in first mode. Get the Iris Lab Access Disc from the dead guard then get some HK ammo from where you entered. Locate the computer terminal around the corner then use the new access disc to open the door to the next guarded room. You can sneak past the guard ahead by crawling into the second opening on the left and hide. Wait for him to go past your hiding place, then quickly run around the corner near the next room. Kill him in first mode with your laser-sight equipped, then go to the next room. You will find a scientist hard at work and Zip calls to tell you not to kill him, unfortunately for the scientist you must kill him in third mode. Now you've done it, shooting the scientist brings in two guards. Let them come around the corner, then you can easily kill them one by one in first mode with your laser-sight equipped. After you killed them, sprint past the turret gun on the ceiling then head for the door on the left. Walk down the passage then stop before going left. Get your back against the right wall then use your laser sight to spot the next guard. He must not see you, aim for his head then kill him in first mode. Walk down the next passage then stop near the left turn. When you see the guard comes sneaking by, Aim for his head in laser sight mode then kill him in first mode. Go near the next room, but watch out for the laser that rolls by. When the beam goes right, go left to get another Rose. Turn around, then wait for the lasers to come and go. Run to the middle then duck for the lasers to pass by, now go forward then go right to the stairs. Go up the stairs then enter the Iris control room. Pull the switch on the wall to turn off the security force field. It only stays off for a few seconds, so quickly make your way down to the bottom then enter the Iris room to get your treasure before the force field is activated. Head through the other door to exit the level.