At the end of Chapter 3 "Sulaco Falls" you will reach the transporter ship to escape from the Sulaco.
To open the door an finish the Chapter you need to activate 2 emergency release.
- Go to the far left Corner of the room and up the stairs, when you turn left you see the first emergency release. Dont activate it now. Go the way around to the 2nd release.
- when your almost there the way in front of you the way will collapse.
- Turn around an you will see a door in the front of you.
Go there and kill the 2 enemys in that room.
Then in the next room and take out the heavy armored enemy to your right.
-Activate the crane switch. Now it take a bit until you can go to the 2nd swich, thats why you want to activate this one first.
- Then simply activate the first one and go on the ramp of the transporter, in that moment a cutscene starts and the achievment will pop.
It's my first solution here and I hope it helps.