In the kitchen area open the cupboard and pull out the coffee tin.   Open the lid of the tin and you will see a piece of paper stuck inside, open the paper flap to reveal a pin code.

Move back to the desk and sit at the computer.  Use the blue code calculator you picked up from the desk, not the hospital one, and use the pin code you have just obtained to calculate the access code.   The user name you need this time is on a clue from the safe in the hospital (Sir Walter's birth and death), you took a photograph of the plaque on Raleigh's Walk which will give you the details (reveal).

Once into the computer you will be able to deactivate the alarm systems.  On system 1 turn off everything.  On systems 2 and 3 turn off everything except the video cameras, if you turn them off you will get caught.  Leave the room using the key code from the hospital safe (reveal) and head downstairs.   You should take off your gasmask now.

Go outside Devereaux Tower and down the sewer cover.   Once inside the sewer head back to the area marked on the map as video boxes.  Move your DLU to the other box (switch it on). 

Then head to the area in the sewers marked 'Bricked up wall'.

At the end of the tunnel head up some stairs to a door secured with a bolt.  Use your can of WD40 to loosen the rusty bolt and open the bolt.

At this stage you could go through and get to into Waterloo Block and the jewels, but the programmers have gone to great effort for this game and there is a more picturesque route.

Once the door is open go back to the sewers and exit via the Devereaux Tower exit.