In the third level when you go to rescue Helm, in the area where you have to place a micro mine on the elevator controls, you can bag salvage points.
After eliminating everyone, two enemies should come running out of the elevator instead of blowing up the controls, you can crouch with L3 and sneak around and get kill moves by pressing X while behind them on them by hiding behind the various objects like boxes and crates.
Also my personal favorite. Hide on the stairs by the elevator and after then men come out and start to walk away, jump up onto the ledge and sneak up behind them and perfom your kill move. Even if they are right next to eachother you should still be able to do a kill move as long as you stay crouched and be patient.
Do this as many times as your heart desires because the men will keep running out until you blow up the elevator controls.