Story-related and cannot be missed. This is the last planet you visit before the grand finale.
*** Spoiler - click to reveal ***Here's more detailed walkthrough:
- When selecting squadmates, please take into consideration they will be your party for the remainder of the game
- After the hard landing, go behind the Mako and kill the Geth including two Geth Armatures
- You will be progressing slowly towards Security Station - nothing unusual, just groups of Geth you have to eliminate
- Once there, if your skill is high enough, you will be able to utilize four Armature Controls to have some Armatures fight on your side
- Open the gate after the fight and return to Mako
- On your way you will be stopped by a "force" field - I won't spoil the details, but through the dialogue you will learn a lot
- Here the race against time starts - follow the pathways of Ilos and eliminate all enemies
- When the timer starts, ignore all Geth and drive to the "gate" as quickly as possible