Self Defense (10)

Kill 10 humans

A decent place to grind this out is near the very beginning of mission seven, “Seegson Synthetics.”

Enter the vents. When you drop down you'll be at another elevator. Save at the save station just outside of this elevator, then turn around and move to the area with the three hostile humans. Pop a flare and toss it in one of the corners of the room to distract them. Wait for the humans to group around the flare, and then throw a flashbang or smoke bomb at them. Walk up from behind and strike them down with the maintenance jack.

This is a more stealthy approach to killing the humans here, so if you are attempting the achievement to complete the game without dying you can do the above maneuver. However if you are coming back to this mission through mission select you can always take out the humans with a Molotov, a pipe bomb, or with the revolver. But remember that the noise can easily attract the Xenomorph.

Reload the save and repeat the procedure above until you've got your ten kills.