Teleport back to Area 51 and, to the right of the teleporter pad (outside of the playable area) will be a shelf with several plates of there. A grenade must be thrown to knock off these plates. After this, a Gersch Device must be thrown at the plates to move them onto the teleporter pad.
IMPORTANT: The Gersch Device must land on or right beside the Casimir Plates. If the throw is not accurate, Samantha will laugh and take the device.
Use the teleporter to return to Griffin Station.
Proceed to Step 7.