During Interloper, there are 4 sections with lasers you have to avoid.
The first one is a room full of lasers you have to naviagate through after you jump down from a vent.
During the second one you stand on top of a pod and have to stand left, right, crouch and jump over lasers. For the jump one, wait until the pod before you passed the lasers and boost over them.
The third one happens when the security system detects and wants to eliminate you.
Lastly you will arrive at a hub area where you have to deactivate 3 force fields. During each section you will encounter lasers while going up or down the tower.
From my experience, you can quick save before and after each section, but you CANNOT save during them. If you fail one and get hit either start back at the start with your quick save or use an auto save that might have happened during the section. This does not void the achievement.
It should pop after you leave the grunt factory/lab with the last jump-pad.