Save your wingman by killing an opponent who downed them before they die 10 times in 2v2 playlists (public only).
Versus - Match Making - Competitive - 2v2 Gnashers
This achievement should come naturally while making progress towards
Work together to take out one of the opposite team. Have the person who isn’t going for the achievement get downed, preferably from a distance. You can then revive your teammate, but make sure they let you kill the remaining opponent.
You could even let your teammate get downed by both opponents, and then you kill them both - depends how good the other team are.
Do not attempt to boost this achievement or you may be permanently banned from playing Gears 4 online, including Horde.