Protect Sig at the pumping station was a mission in Jak II. After beating the Scatter Gun Course Krew offered Jak the option of becoming a wastelander for him. This time Krew sends Jak to the pumping station, where he had to watch Sig's back as he hunted for some new metal head trophies.
The PlayStation 3 and Vita versions of this mission are related to a trophy named "Signature Moves", completing this mission will reward you with a bronze trophy.
As soon as you enter the pumping station you'll see Sig crouched against some flora to the right, approach him for a cutscene where after he'll immediately head forward and begin to fight the Metal Heads here. This mission introduces the juice goon, a metal head with a strong short range attack as well as a good amount of health. It'll often come in relatively large groups in this mission as well.
Sig can handle his own fairly well plus you can't hurt him with the Scatter Gun. You can either split up and handle some of them by yourself or use Sig as a decoy and rely on the Scatter Gun's blast area to hit any metal heads near him. Climb up the metal structure and Sig will blow up the container on the left creating a new passage. Head forward here on your own, fight some enemies (take care of the znorkle tooths that jump out of the water) and hang onto the bridge to lower it.
Now comes the first spyder gunner Sig will again begin charging his Peace Maker and you'll have to protect him from znorkle tooths that jump out of the water. Try to hit them with the Scatter Gun as soon as they show up so you can knock them back and kill them in one hit as they fall back into the water.
Next is the first dangerous fight in this mission, there'll be a large number of juice goons (and some glubs) on the beach up ahead. After clearing it Sig will charge up for another spyder gunner, repeating the last defense bit. Move on towards the bridges and after lowering the second (there'll be enemies) Sig will charge up for another gunner trophy.
Follow Sig to another group of juice goons and glubs, after clearing these you'll have to protect him again so he can take down the fourth metal head. After crossing the water you'll be ambushed by more juice goons jumping from the pipe above you. After killing a couple Sig's gun will jam and you'll be forced to defend him until he can repair it.
Now is probably the best time to use Dark Jak, which makes it a lot easier to get rid of the metal heads. Without it you can also rely on the Scatter Gun; just circle Sig and shoot anything that comes close. After this you'll only have to protect Sig once more from znorkle tooths as he charges up for the fifth trophy.
This mission was included on a demo disk given away with a PlayStation 2 at the time of the game's release.