To obtain this achievement, you will be using your Displace power.
Displace allows you to deploy a marker by holding
, and then swap positions with it by pressing
You will want to have Displace active then place your landing point under the feet of a NPC or enemy character and then teleport to that spot before that person moves. You will warp to your landing spot and kill them instantly, while you take some damage yourself.
I did it on a NPC that was idle in one spot.