This mission took me awhile to figure out, especially when you have to do it in under 10:00 minutes. Here's how you do it.
First, make sure you finish the previous mission with at least 1 grenade AND the 50cal Sniper rifle (grap 2 from the guards in the towers in the last mission).
Okay.. When the mission starts immediately crawl around the metal platform to your left and to the other side of the grid floor. Crawl diagonally off the edge heading towards the back corner of the roof. Belly-flop onto the roof. Crawl to the back corner of the roof behind the stairs. Lean off the edge of the back of the building. As the guard patrolling around that back corner behind the stairs turns the corner, track him with your sights and put a single shot straight through his head. This shot is critical! If you miss, he might stop for a moment and you can pluck him again. Otherwise, you might as well start over. If you've done it right, he collapses without a sound.
Now, belly-flop off the back of the building. Crawl alongside the stairs . Look through the stairs at the window. You'll see the head of a guard. You have to make this shot! Take him out with a single headshot through the window. If you miss then take a quick second shot before he does anything stupid.
Turn, and crouchwalk to the guard closest to you by the truck. Break his neck. If you shoot him then the other guard runs and turns on the alarm. Then, fire a single shot into the head of the other guard in front of the truck.
Stand up and run around the back of the building and hide in the last bush by the fence so you are facing the door of the guardshack. Fire a single shot into the door to get the guard to open it. When he opens the door, fire one into his head or two into his chest. Hint: When he opens the door, his head will be just at the spot where the white-dot is on the outside of the door. When he goes down, stand and run into the shack and open the gate.
Now what you are going to do is to take out all the guards on the other side of the huge door. Here's how you do it. Position yourself in the middle of the road approximately between the corner of the fence and the next lamp post towards the huge door and crouch. Crouch in the middle of the road facing the huge door and fire two rounds straight into the door.. This causes the guards to open the door. Immediately switch to a grenade and toss it high and long then lay flat and switch to your sniper rifle. If you tossed the grenade right then you've taken them all out in a single blast. If there is one still standing, you can drill him with the sniper rifle before he sees you. Sometimes I clear them all with one grenade and other times I have one guy still standing that I have to take out.
At this point, you can stand and run and search the bodies for grenades which you'll need at the end of the mission. Also, if you find an RPG, pick it up and fire at the APC parked right there! You'll kill the APC and all the guards inside of it so there'll be less guards hunting for you at the end of the mission. (Note: Anya warns you that you are leaving the mission but just ignore her). Run back out of there and lay down in the street where you were laying before.
Now, you have to take out ALL the guards by the Rocket and in the tower. So, get your sniper rifle zoomed in on the guy standing at the bottom of the tower. Drop him. Now, take out the two guys by rocket. Shoot when they are walking towards you (square in the chest) or away (square in the back). Bang! Bang! They go down.
Now, you've got 3 snipers at the tower. Take out the sniper on the top LEFT first. Then, take out the guy directly below him. Then, drill the sniper on the top RIGHT. Bang! Bang! Bang! Three quick shots.
At this point, you've taken out all the guys guarding the rocket and you've wiped out a bunch of guys behind the huge door waiting to come out when the alarm sounds.
Now, get up, reload, and run down the road and around the fence to your LEFT. Get in a position on the grassy area. There is one good spot to the right of the trees. The 50cal makes a big noise so here's the trick. Position yourself so you are just peering over a hump in the ground. You can fire away with that rifle and they won't see you. If you're too exposed then they'll see the blast from your gun and start returning fire. Be sure to be aiming straight through the gate itself. You want as much visible area so you can kill the guards guarding the fuel tanks as they come running towards the gate to see what's happening.
Once you're in position, take out the guards on patrol. Try to hit them square in the chest as the come running towards the gate. Try to hit them in the few moments as they stop and look around. And remember that you've got to also take out the guard in the guard shack who keeps running in and out of the door. He's tough to hit but you have to take him out too!
You've got a big powerful scope on that 50cal sniper rifle so aim and fire. You should be able to take these guys out from your distance with only a few missed shots. Be patient. You've got time. Don't be seen!
After you've cleared that area, get up, switch to carrying your knife and run to the guard shack. Use the computer to open the gate. Run directly to the first valve handle between the two big fuel tanks. Turn the handle. Now, jump onto the pipe just to the left of the turn-handle and run along that pipe to the back fence and jump off. This is a shortcut to the second valve handle. Turn the second handle.
Run out of there and make a bee-line straight for the base of the gantry tower and ride the elevator to the top.
Going up the gantry tower causes a helicopter full of guards do land in the helipad below so you don't have much time. Exit the top of the elevator and run straight to the top of the rocket and insert the chip into the rocket.
Now, run down the stairs until you get to the control panel on the BOTTOM GANTRY. Use the control panel. The alarm sounds. Run up the stairs to the control panel on the middle gantry. Use that. Run up the stairs to the control panel on the top gantry. Use that. Run up the stairs to the very top of the tower and quickly slide down the cable as fast as you can.
While you're sliding down the cable, you'll see an APC heading down the road towards the tower. That APC is full of guards who are going to exit the APC and run to the back of the building with the big blast-doors.
When you hit the bottom of the cable, jump down onto the roof. Go around to the front of the building and step off the edge of the roof towards the front of that building. Run straight for the road. Toss your 50Cal sniper rifle. If you don't have any grenades then you have to run down the road and pick some up from all the guards you killed with the grenade blast. There is almost always a few grenades here.
Then, cross the road and pick the lock on the fence gate. Don't run right along side the building itself because this gets the guards in there running around crazy. Run a bit away from the building.
Here's the trick. Run up to the very back corner of the building and lay flat. Be careful because all the guards from the APC are running around the OTHER corner of the back of that building. Get out your map computer and wait until the guards check out the area and start walking slowly back the way they came. When they turn, crouch walk over the hill by the back corner of the building and head down to the control panel. Open the big blast-doors. Crouch walk in and use the control panel on the inside to close the blast doors.
Crouchwalk. Usually the guards are gathered by the end of entrance ramp leading to the computer area. If I see them all gathered together, I stop and quickly bounce a grenade in their direction at take them all out in a single blast. Otherwise, if they are not gathered together then I take them out one at a time.
Either way, you have to deal with these guys. Use your silenced machine gun and pluck them with 2 or three shots in the chest each.
Once you get to the top of the ramp, if there are any technicians around then you can pluck them. Use your head to figure out how best to take these guys out.
When the last guard and technician goes down, stand and run to hit the button to close the blast barrrier wall. Run to the second switch BUT DON'T HIT THAT SWITCH! Get out a grenade and crouch! Here's what you're going to do.
Immediately after you hit that second switch a big door will open on the far end of the computer area you are in and a whole bunch of guards will come pouring out. If you are standing up when that door opens then these guards see you AND start firing. If you're crouching down when you hit that button then they don't see you! So, crouch and hit the button.
Then, immediately turn and toss your grenade right through the second set of windows from the far RIGHT. Toss the grenade straight through the window. If you've tossed it right, you take out ALL the guards exiting that back door in one big explosion. If you've got a second grenade then quickly toss that just to be sure.
Now, get up and RUN around into the area where you just blasted all the guards and hit the launch switch. Mission Accomplished!
I did this mission in 8:57 without being seen, 100% health and 100% accuracy.
Tough mission but you can do it!