Obtain 11 000 points in the Shanghai mission in the Campaign
This is another easy mission and it features a plethora of multi-kill opportunities. You can use these to unlock Wrecker, for achieving 10 multi-kills in this mission. There are multiple instances where you will find a weapon crate nearby to refill your grenades while throwing them at enemies. The best place for this is the helipad on the roof, which you will reach after rescuing the VIPs. One of the easiest multi-kills in the game will be available when you first step outside onto the roof. Two enemies will be walking down the stairs on the right. Unload your assault rifle on them and you will likely kill both at once. After that, go up to the helipad and stand next to the weapon crate. Throw grenades at the enemies and try to time your shooting kills with the explosive kills.

Please see Above and beyond the call for point-scoring tips.