Before you take to completing this objective, there are two optional things worth doing. Take a look inside the ammo depot on the right (screenshot 1). In the area to the left of the landing pad you can also find the last Dog Tag in this mission, pictured on screenshot 2 (Sgt R. Siwiak).
There are three fuel lines to disconnect; you can check their location on the motion tracker. Before approaching any of them, make sure to clear the area of any Xenomorph in the closest vicinity, because even though you can't take any damage while working on the lines, you'd still be surrounded with no way to escape. Approach the lines one by one, but be aware that disconnecting them would spawn new aliens around you.