It happens that there is a very small spot in the mountains near Sindragosa’s Fall – you’ll need to do a little climbing and precision falling to get to it. I’ll try and find the coordinates for you – where, if you die there, a small section of the Horde airship is within your rez distance during its pathing.

So first: get your hands on a couple Dark Runes; they’ll knock 600-1000 health off. Get to that point in the mountains, have your friend duel you down to as little health as you can manage, and then pop a Dark Rune. This will kill you, so you’ll probably want to be in trash gear or naked when you do it.

When you get back to your corpse, don’t rez; instead, fly as far straight up as you can and still have the rez indicator on. Eventually the airship will fly around to you and you’ll be above one of the gunnery platforms. (You may want to let it pass once to gauge where you need to be, and then go make a sandwich until it comes back.) When the airship gets under you, rez and you’ll drop to the gunnery platform, from which point you can run up to the Brother and get your achievement. :)

I’ll see if I can hunt down the coordinates of that spot in Sindragosa’s Fall for you!