Frenzy is one of the 2 new game modes in the DLC and is very similar to "Gun Game" from Call of Duty: Black Ops. It is different in that your loadout will automatically change every minute and it is random what weapons you will get.
The simplest way to get this achievement is to keep killing enemies (or boosting partners) until you reach the max score of 10,000 points (which is one of the requirements for the achievement "Flawless Victory", the other requiring you to have the most kills). For this achievement, you just have to get 2 kills with each weapon you randomly get per minute.
There are a few things to be cautious of and that is getting 2 kills with the first weapon as the beginning may involve many players scrambling around and you may miss the opportunity to get 2 kills within the 1st minute. The next challenge is getting at least 2 kills or more with the last weapon you have. This may cause issues because you may only need 1 kill to win the watch and this will forfeit you getting the achievement. If your score is quickly reaching 10,000 but the timer is about to reach another minute, then save the last 2 kills you need for the next round. Your score (if you have a multiplier) should be around 9,000 points making you need only 2 more kills to win.
To clarify, You are only responsible for getting 2 kills with each weapon that you get within the time it takes you to win. In conclusion, get as many kills with the 1st weapon then keep killing with the 2nd loadout until you reach around 9,000 unless you can finish before the 3rd minute (3rd loadout) starts. If you can't win in the first 2 minutes (1 minute is very unlikely), then finish your last 2 kills or more with 3rd weapon.
Personally, I was in a group with people where we focused on 1 person getting it per game and we typically finished the 10,000 points needed to win in less than 2 minutes. It can be difficult for the first minute with finding a common meeting ground but gets easier once the player gets 5 kills because a giant 5x symbol appears over their head essentially making them an easy target to locate. Sorry if the wording is confusing, just comment if you have suggestions to make this solution clearer or message me if you have questions.