GHOST 1.0

As you enter the Chunker for the first time (You need the Red Card, them go to the starting point of the game then head left -you'll have to go through a lot of Turrets, Robots and through two Dangerous Steam Pipes rooms) there's a stair just below the 3D Printer Room. Go down in the stair and, just after you change rooms, go into Ghost Form while still on the stair because she will not fall from the stair and is a safe spot as the robots can't see you there. Then, hack into one of the Security Robots below and jump into the Crusher below the platform. This will unlock the achievement and this room's Hidden Soul for you to gather.