The beginning of the 4th level A Change in Course is the first point you can achieve this, at least without any DLC equipment. By now you'll have your darts and either Smoke Bombs or Noisemakers equipped.
At the beginning, kill the first guard however you want, and in a vent underneath him, you'll find a box containing Spike mines. Go a bit left to where you'll see a 2nd guard. Hold
to go into focus, pressing
with each item to target something or somewhere to use each one (all whilst still holding the trigger).