Diamond store is the frist map which need coop in stealth mission, you could solo run this map but is difficult start increase, however the call is on you.

1. two players at least
2. have two ECM in hands
3. all weapons in silencer

since the crowd in store have at least over ten of them, plus there are several people scatter over outside, so solo this mission really need patient, else you could do it's with other player or friends.

1.down cam room: the entrance could be left side or main door only, if you need to solo this mission than you have to restart the mission until the cam room entrance spawn on left side, so you could possible down cam in ease.

2.down guards(or swipe out outside crowd):after frist step you could move upstair, most of time there would be two guards on 2F, some time have manager with it take them down and answer the paper, clear outside frist if you was in solo, since there would be little time for you to react inside shop, so if any outside people were tirgger the faliure rate of your mission would be huge.

3.land ECM, crowd control: the ECM could buy you some time but not much, kill or tie them up, after that just moving the loot and get your reward.