Easy Spin Doctor Achievement Answer?

Not a question but i thought I'd provide an answer since i was having trouble with this. At the start of the Ruins Level where you have to activate the three predator switches to open the door. When you open it a moderate sized group of aliens will be crawling on the walls.Throw your disc at them and on the return trip the disc should take out a second alien. Gamertag=SDF Brimstone