1) Start Chapter 6: Shutdown.
2) You will fly to a few places but the achievement can be gotten at the Production Tower which is the third tower.
3) You will be instructed to reach the control room.
4) Enter the gravity elevator.
5) Cross the energy bridges heading towards the objective.
6) You will see two Hunters.
7) Stand near the edge of the platform.
8) One of the hunters will run at you.
9) When it is running at you fly up and avoid it using the jet pack.
10) When it falls off the ledge, you will get the "Explore The Floor" achievement.

Here is a video explaining: