Thanks for anyhelp...TheFoole.
Anyway, if I remember rightly the door is coded and you need to use your decryptor to get into the door. Once in flip out the little CD and press the action button on his computer. Once the code has popped up 2 guys will burst through the door so take them out and then make your way into the main hall and go to the big double doors. Open them using the card swipe on the right side and then go into the room. As soon as the computer pops up press the action button and then make fast for the stairs leading to the roof!
Hope this helps.