Destroy the Tetranode
Travel down, recover ammunition and approach Voss (#71). Commander will explain you the general purpose of the new mission. Wait until the engineer will open the door and follow the group. Try to fight with enemies, but watch out for ammunition - there aren't many places in this level, where you can recover it. Ammunition will be undoubtedly more useful to you in the future.
After short walk, you will reach the operations room (#72), but there won't be many things to do. It is necessary to raise the temperature (at present it's able to kill all soldiers).
You (as the assistance) and engineer will be assign to the task. Be aware that the Gladiator is waiting for you in the first chamber (#73). Watch out for Strauss and try to defeat the enemy by yourself.
After the short walk, you will eventually find the terminal. Strauss should take care of it (#74). For the time of the operation, you'll have to take care of enemies (Sentries) and Machine Gun is the best choice for you. After the fight, you will learn that the engineer must be left in current position and you're necessary for remaining members of the team.
Return to Rhino Squad
Return as quick as possible, systematically eliminating enemies during the walk (there will be substantial number of the opponents in the hall, where the Gladiator has shown up earlier). Reach the operations room and help others in getting rid of the next enemies. Go with allied soldiers. Few dozen seconds after, you'll get to the vast tunnel. Though struggle awaits you there - it would be good for you to have big ammunition reserves. After the hard clash, run with Voss to the door and (this time alone) move further.
Deactivate the Forcefield
Walk straight ahead, killing all enemies on the way. Jump on pipes in the big hall (#75) and get to the control panel (#76), where you must switch off the force field. If you go there, you'll reach the small ammunition storeroom (#77), so do it.
Return to the Convoy
Return to the team. You'll see that all squad's members are gathered near the trucks and single engineer is trying to fire EMP up. Unfortunately, something will go wrong again. Suddenly, the Harvester will appear form the opposite side of the tunnel (#78) and destroy the weapon. Try to avoid cars and don't shoot at the robot. If you do that, you'll only lose valuable ammunition.
Wait until Voss will stop mourning dead colleagues. After a while he will open the passage (#79) to channels - go there. Once inside, move forward and don't look back. You'll run into the first ladder in channels (#80). Climb up and quickly run on the other side of the passage (Harvester standing above you is able to crush you, so be careful). During the crossing, you will get the new weapon - HyperBlaster. Proceed patiently forward. Finally you'll find the ladder that leads to the bigger hall. From there jump on pipes (#81) and go up.
Walk ahead all the time and exterminate enemies (for Sentries use Machine Gun). Knock all enemies out in the last room and take stairs to the top. Here you'll find the elevator (#82). Use it to get to the main part of the complex.