Kane & Lynch 2: Dog Days

I got this in Arcade mode, playing Subway. After you've finished looting, some of your team will take cover in front of the train by the wall on the left-hand side. Stand on the platform in front of them (in their line of fire) so they will hit you when they fire at the cops who come down the stairs at the other end of the station. If one of them hits you they will get a yellow card.

Now you need to get downed so you can kill him before his yellow card times out. Don't shoot the dog that comes to attack you. The dog will down you and you can shoot the yellow carded teammate and get the Achievement.

It requires some luck with timing, but I got it on my third attempt using this method.

You get a yellow card when you shoot a teamate (not a traitor, and not in Cops and Robbers).

Two ways this can be done.

1) Legit - Wait till someone that is not a traitor starts to shoot you. When they down you, pray that you end up killing them while still downed. After the round is over, achievement unlocked.

2) Slightly less legit. Have a buddy search for the game in Undercover Cop (seemed like it was easier to get in the same game). Try to host a match (Suggested Map: Airport), just so you know it won't be killed while you are going for it. Once your buddy is in, ready up and force start it once there is four guys. When the game starts, hang back while your team goes to the objective. Then boost it that way.

Easy.

When a friendly criminal shoots you a few times, they get yellow-carded temporarily. You can take out friendly criminals without becoming a traitor if they're yellow carded. When they're yellow-carded, you have a limited amount of time to shoot them.

The Subway is a good location to do this, as described by Destrier. As you're going for the evacuation point after looting, your team will take cover on the left-hand side. Stand between them and the cops coming down the stairs so one of them gets yellow carded. Then, let yourself be downed and kill the yellow carded team member. The dog that comes to attack you can quickly do this. Also, once you go up the stairs there will be several enemies shooting at you. This also provides a good oppotunity to stand in the line of fire of your friendlies and also to be downed quickly.

Another good place to get this is the Harbor map. Eventually you'll come to an area with a car right in the middle to take cover behind. Quite a few enemies will begin to shoot you. Your friendlies will be behind the car shooting at them. This provides you with another good opportunity to stand in the line of fire of your friendlies and allow one of them to become yellow carded.

Search for locations where your friendlies shoot consistently and for a long time at enemies in a specific location. Also search for locations where there's a good balance of cover, so you aren't killed, and enemies who can down you quickly, giving you more time to shoot the yellow carded criminal. This takes some patience, timing, luck and practice. You should be able to obtain this achievement in a few tries.