I had read that this achievement had been fixed, so I gave it a try for the first time. But after 3+ hours I didn’t get the achievement. I didn’t take out any Wraiths by jumping on them and giving them a grenade or melee, I didn’t use any turrets, etc. The only thing I did do was get on the Scarab to take it out, but according to my reading that doesn’t count as getting in a vehicle because it’s not drive-able, plus I’m not really sure how you would take it out down without getting on board. At least not without a tank, but that would obviously void the achievement. I’m sure there’s probably some other way, but I didn’t bother looking it up because it was my understanding that it wasn’t an issue. Does getting on the Scarab void it? Was it ever really fixed or was what I read incorrect? Or did another update after the one that supposedly fixed it un-fix it? I really wasn’t even thinking about how irritating it might be or how long it might take before jumping in, and I didn’t realize how useless the AI tanks would be. But once I’d gotten pretty far in the level I wasn’t going to turn back.
Edit: Well one of the members here was kind enough to let me tag along while he did a speed run and the achievement popped that time. I don’t know if it was just a matter of the achievement needing to be redone or if jumping on the Scarab voided it. But I have it now so I’m not mad about it anymore. It also popped several other achievements because I’d never played co-op with anybody and I hadn’t beaten the par score on The Ark yet. As the Who Needs Them run was my first attempt on Legendary and I did obviously didn’t break any scores since it took me 3+ hours, countless deaths and I killed a bunch of Marines for their weapons and ammo. I think I was about -7000 by the end.