Okie dokie so to get this achievement first and foremost you will need to go through the level until you come up to the bridge where you can rotate each of the sides.
Now when Wall-e is rotating sides there is a 'map' on the left side of you that is red, when you free all of the reject bots from each section it will turn green, letting you move on and rotate the bridge to the next section.
You will have to go back to the control room to continuously rotate the bridge!
When you release the final bot the achievement will pop!
Good Luck!