Destroyed all the Helghast Tanks in the Senlin Beach section


Chapter 3 Pyrrhus Evac Senlin Beach, moving on from the part in Smoking Wrecks above, the 1st Tank will appear from behind the debris right in front of you, followed by 2nd tank on your left on the highway further up. Take them out and as you move further forwards a dropship appears and your vehicle will take the path to the right towards a Helghast nest and the 3rd tank will be to the left of it, right beside the dropship that crashes soon enough.

Your vehicle moves over to the left behind your ally who makes an abrupt stop and the 4th tank is directly in front of him. The trophy should unlock right after this point.