The guards in general are more alert in thief 2, in this mission they even cheat. I had a situation when i was on a dark room and hide behind a table with carpets around, and a guard entered doing a patrol and turn around the table directly to me, then i circled around, on carpet, to keep the distance and the guard turn around and went circling the table in the oposite direction again directly to me. I keept like a minute or two circling the table to one side then to the other and the guard always changed his patrol to the side where the distance was shorter to me. In the end i had to load a save
