Deus Ex Mankind Divided - ****! Taser Fist! Trophy / Achievement Guide - Lock-On and deploy the Quad Arc upgrade of the Tesla Knuckle on four enemies at once. [Bronze / 10G]

You can do this anytime after the third main mission (where you fix your augmentations). Combat trophies work only on enemies (not civilians or policemen). Enemies are red in Smart Vision.
I did it in a russian underground casino. You actually go there during "Side Mission 4: The Calibrator". Either do it during this side mission or return later after completing it (enemies will still be there).

You must fully upgrade the augmentation "TESLA".
There are many enemies close together in the casino. Get close to them and hold the assigned button to target 4 at the same time. Make sure there are no objects in the way. Hit 4 at once and the trophy unlocks. The trophy wouldn't unlock for me until the enemies entered combat and started shooting. If you experience any issues, shoot up the place, wait for enemies to attack and use Tesla during combat.

IMPORTANT: Make a backup save before buying the aug and going in there! You can farm all other combat trophies in the same spot. Reloading the save will also reset the augmentation and give you your praxis kits back. So you can quickly upgrade another aug for a different combat trophy.

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