You will be able to get this achievement during the escape from Kowloon.
Just make sure you use only double wielding weapons. You can also use your melee and grenades weather it be flash, stun, or what ever.
As long as you do not shoot with a single wielded weapon you will get the achievement as soon as you are off the rooftops and hit the ground just before you have to pick up the pistol and defend against the Spetsnaz assault before you enter the van at the end.
Here are some tips that helped me obtain this:
- Shoot in small bursts. Shoot with each weapon with small bursts. Do a small burst with the left then the right. Seemed to keep the shots more accurate.
- Use your melee when you can.
- Use Frag and flash bangs often. Especially to get the ones in windows and and high points, otherwise you can run right by most of them (the ones in windows and other high points, also the ones you flash bang if your fast enough) to get to your next location.
- If you accidentally pick up a single wielding weapon just make sure not to shoot it or you will have to start over.
Note: I have obtained this achievement on another account. It was compromised so I had to switch to another.