This missable achievement can be earned on the second mission. At some point you'll start looking for Ivan Jacobi. Following the marker to his apartment will reveal a note that says he's practicing a speech in a particular square in the city. This square isn't far from the apartment (essentially, turn left when you exit the front, then left again when you can). When you get there, you'll go up some stairs and see him pacing around a stage area, with a bunch of guards around.
On the left are some stairs heading down. You need to get down the stairs without being seen; judicious teleporting or using Semblance on a nearby guard are two approaches. Once downstairs there is another guard you need to eliminate. From there head to the room on the far right, where you can find a wooden ceiling with the trap door and a nearby handle (this room also has a hole in the wall which you can use to escape and/or explore afterwards). Wait for Jacobi to walk onto the trap door (dirt and dust will rain down) and pull the lever to drop him and unlock the achievement.