Left Hand 2.1
There will be a cutscene involving a room filled with cybernetic brains and when it ends, you'll find yourself in the room you were previously in. You'll initially be attacked by three guards but a fourth will show up shortly by coming out of a side door. This fourth guard has this left hand.
Left Hand 2.2
After the section where you control the Dwarf Gekko, run into the same room with Raiden and one of the guards on the bottom floor will have this arm. Remember that if you stunned enemies with the Dwarf Gekko, he may be lying on the floor unconscious.
Left Hand 2.3
After the section with the Dwarf Gekko, you'll enter the same room with Raiden. Open the door on the bottom floor to continue and you'll enter a hallway. You'll eventually come to a pair of guards in a hallway. One of them will have this hand.
