Mission 8: Third Echelon HQ
Find the transformer rooms to plan the C4 in them.
Infiltrating a building of such high security measures would be preposterous for any other person, but not Sam Fisher--he's got a vendetta to settle and he intends to make it clear to all members of Third Echelon that he's still the sharpest tool in the shed. The plan now is to blow out the power just long enough for Sam to sneak inside before the emergency power generator brings security back online. Seems sound enough, except this must be done without alerting guards or getting detected by security cameras, which are denoted by the sweeping cone of light. From the origin, follow the back wall to some motorcycles. Climb up here and land upon the lone security man inside the control booth.
After swiping his security card, proceed very cautiously through the door. The security camera's field of vision covers just to the doorway, so if Sam just haphazardly charges out the entire operation will be compromised. A single guard patrols this section of the parking lot, along with three security cameras. Move from the booth out to the parked van on the right, then dart out to the vertical pipe located between the white car and the dark-colored van. You can choose to take out this patrol in the process, but he can be left alone, as the first transformer board is in the room just ahead.
After planting the C4, climb into the vent and hang onto the ledge, waiting with zen-like patience for the patrolling guard to make his way just under Sam. Knock him out and continue up, hiding in the comforting darkness. There's a still guard at the very end. Grab him and drag him back into the shadows before snapping his neck. The third guard can be left alone, but make sure he doesn't see Sam creeping across the parking lot. Head toward the black SUV to find an opened vent behind it, which leads directly to the second transformer board. With both C4s now in place, it's time to head to the elevator.
From the second transformer board, head up the steps and through the door. In a low crouch, very quickly shuffle over to the ramp leading down and hop over to the rail to submerge Sam in darkness once again. The elevator door is just within reach, but be careful not to get seen heading into it.
Riding the elevator up, Sam arrives at the receptionist's desk and, shortly after making his name known, detonates the C4 charges. There's only a small window of opportunity to slip in through the closing security doors. The guards in the vicinity, however, are on full alert and will gun down Sam. Having a few Flashbangs handy to blind them allows him to at least slip through the doors and reach a save checkpoint before either doors clamp down or the guards gun him down. Run down the stairs and then jump up above the light fixtures to avoid the security personnel just around the corner.
Meet Grim's contact in the office area
Tip-toe right above and past the guards here, heading toward the right, which drops Sam off in an unmanned room. Leap out the window and shimmy over to the right to find three more guards sweeping the region. If you stay put, all eventually come toward the ledge, at which point Sam can grab them by surprise and toss them over the balcony. Hug the right wall and make a run for the short corridor, which brings Sam to another densely populated room. A couple of security cameras have come online, but they should be no problem if you choose to travel above the light fixtures. There's one last security camera just above the door leading to the server room, but time its movement to snake past it.
In the server room, the timid Fryman, who turns out to be Fisher's biggest fan, provides Sam with a new gadget, Sonar goggles. These babies allow Sam to see in the dark, through walls, and pick up heat signatures of surrounding people and laser grids. He warns Sam that some of the Splinter Cells may be equipped with the same gear and to exercise caution.
Reach Reed's office in the restricted area to get the details of his plan.
Security has somehow caught up to Sam in the server room--it's time to bail. In the server room, climb up above the ceiling and scout out the four guys in the adjacent room. Take them out however you want. As you have Sam trace his steps across the previously visited rooms, keep in mind that fresh new guards will always be looking forward and not really backwards. Stick to the ceiling and quiet takedowns, if necessary. At the lit corridor, mad dash over to the balcony and leap over it before anyone lands their sight on Sam's shadow.
Eventually, Sam reaches a new section leading toward Reed's office that is heavily rigged with invisible laser beams. Some of these beams move and some of them remain stationary, but all of them are wired to unleash a flurry of turret fire if tripped. Activate the Sonar goggles and get to work, crawling under one laser and vaulting over objects to bypass others. Rotate your camera around to get a more accurate viewing of how much wiggle room there is and whatnot. At the end, climb over the metal detectors and head toward Kobin's voice. Here comes a second chance to interrogate Kobin and also get some payback for what he did earlier.
Go see what you can find in Anna Grimsdottir's office.
As soon as Sam leave's this small office, three Splinter Cells equipped with Sonar goggles burst through the skylight with the intent of hunting Sam. To combat the powerful trio, prepare a small trap for them using a Remote Mine just outside Kobin's office. Go out to trigger their entrance and retreat back inside to take cover. Wait for them to come to you (and they will) and set off the first explosion. If any are still alive, take care of them with the shotgun or any other weapon.
Four more regular sentries flood into the room from a newly opened corridor. Feel free to put them out of commission in as a boisterous manner as possible. The next corridor features more invisible lasers, but traversing this corridor would require moving from room to room and then climbing up the pipes running along the ceiling.
Enter the next room and hang a left into the work area here with a single patrol most likely working his way to the other end. Follow him down, and when he makes a U-turn to make his way back, head out and vault over the divider to the floor below. Assuming no one has yet to see Sam, travel quietly to the shadows on the left side of the room. This continues down the room, past all the security personnel circling the floor. At the end, wait as the two guards here start to look away and aim for the stairs that lead up to the second floor. If all goes well, you will have slipped by all of the guards on the first floor.
The second floor presents a much bigger challenge, as the enemies here come equipped with Sonar goggles. Hopefully, you have Portable EMP charges still on hand. Blast a few and make a run for Grim's office. Otherwise, you can utilize the area above the ceiling to take care of the hostiles.
After learning the hard truth in Grim's office, Sam now has enhanced superhuman aiming abilities and unlimited Executes at his disposal. Sprint through all the rooms, headshotting everything in sight, and to the elevator to end the mission.