Warden Eternal assassination help

I assassinated Warden Eternal in Firefight and ended up not getting the kill nor the points for being a part of the takedown. I played a ton of Mythic this past weekend and not one assassination counted toward the commendation. The one in Legendary got me really confused since I got nothing for it. What am I doing wrong? Clip is here: tuhin94's Xbox Halo 5: Guardians clip 34128477. Find your Xbox clips on GamerDVR.com.

As a side note, I did not go for assassinations during every match of Mythic. The few times I got the kill shot with my tank, the commendation counter increased.

Sometimes when you go for assassinations teammates will end up killing that person (or Warden Eternal for this matter) before your assassination does. I would just go for damaging the Warden next time and not focus on assassinating him.

I would only worry about assainations​ with warden eternal when you have friends to play with. People can shoot him when he has a sliver of health and it will count as their kill

If you are in a good position and have good timing, you can assassinate the Warden without much fear of getting your kill stolen.

Yes. It’s a fine line to tell when the warden can be assassinated. When you do, the warden has plenty of health to where no one else but you can get the final kill.

Its useless to assassinate him,you rarely get the kill.