On The Sword, if you go to the stairs that lead you to the place where you start on escape, there should be two pillars on the other side of the stream. On the side which the guard comes through , there should be two faces. The one on the left has a tongue which you can use. Note that it is not there on Thief: The Dark project. Use it, and the locked gate in the stream should open. Swim towards a green opening, and keep on swimming down the red tunnel. When you get to the end you should be in a place where Garrett (and guards) is big, and there is a breath potion surronded by stones which you will need. There should be some water past some tiny buildings, and swim down this to get to a room where garrett and guards are tiny. I think this room is where Garrett meets Victoria and Constantine. You may need to save alot.
I tried this on Thief Gold and It Should work on thief The Dark Project. If not,I'm sorry. Go to the Training mission and play it on expert. After figting the Gaurd, follow him back to where he goes and there should be a wooden door. Break it down with your sword. Inside there is a Basketball Court and a bedroll with lots of funny stuff.