The three rotor mechanism is shown here fitted into a box. The top part of the box is a sliding sleeve which is free to move up and down over the top half of the mechanism's case.
This blade, below, is part of the sliding sleeve. Wwhen the three rotors are aligned the blade slips into the slots in the rotors allowing the sleeve to move right down.
With the rotors unlocked the sleeve can slide right down to reveal a drawer.