The World is Not Enough Walkthrough:
Night Watch
This is definitely a level you play a few times to figure it out. In essence you are trying to bug the various telephones without getting caught. This means there's a lot of figuring out what pattern the people walk in, and how to dodge them.
Start by going through the room right next to yours, and bug that phone. That's easy.
OK, out into the hallway. Sneak up behind any guards you see and tranquilize them, you should have time to get along before they wake up again. There's an elevator to the left, take it upstairs.
You'll need to time your moves in here to get to the 3 phones. You can use the radio to distract the guards if you need to.
OK, back downstairs. There's one more phone to bug in the pool room, by the bar. You should be able to tranq the guard and get to this in time. Then it's just a matter of heading into the garage and finishing the mission!
The World is Not Enough Walkthrough