20.2. Underground: Part 2 | Campaign Duke Nukem Forever Guide
Last update: 11 May 2016
After getting out of the shaft, dive and follow the underwater corridor to the airlock which you have to open to reach the flooded turbine. You can refill on air using the air bubbles appearing here and there. Once inside, look out for the blades which can hurt you pretty badly.
Once you swim beside the turbine, you will find another airlock - this time an open one. Now you will understand why I told you to keep the Ripper. After swimming into the corridor on the other side of the airlock, you will be attacked by a group of Octababies. Try not to get surrounded and keep an eye on your oxygen meter.
Return to the surface using the ladder and you will find yourself right above the turbines. Jump down onto the crates below and turn on Duke Vision, as lights are going to be turned off.
Go down along the corridor from which the rocket has been launched. Look out for enemies lurking in the darkness and cocoons from which Pregnators hatch.
After clearing the room, go up the stairs back to the turbines and move further along the corridor filled with crates and barrels.