In Half-Life 2 Episode Two there is a "Payback" achievement. Its description reads:
Kill a Hunter with its own flechettes.
I have spent quite some time trying to get that achievement but I am not sure how to do it. I have tried to pick up the flechettes by hand or with the gravity gun. I have tried standing so that another Hunter shoots the Hunter I want to kill. I have tried hitting a Hunter with my car while its flechettes stuck to it but none of them got me the achievement.
Suddenly I received this achievement when I was throwing some stuff at a Hunter with the gravity gun killing it in the process. I have no idea why that happened, maybe there were flechettes attached to the stuff I was throwing at it.
What is the proper way to get the achievement? Are you really only supposed to throw stuff at the Hunter that happens to have some of this Hunter's flechettes stuck on it?