I am so frustrated, in the last part of the France level after you meet..

All you have to do is go back into the vent and go to the other room and wait for the barrels to go off and then go back into the vents and then sneak through the white fog with thermal vision and shooting everyone without setting off any alarms and go through the last door and then I think your done im not positive but that should get you past it.

Jump back into the ventalation shaft that you came in from. Do you remember a bunch of steam-like stuff blowing inside the shaft when you entered? The steam will now be gone, so head toward where the steam originally blew from.

After talkin to the man on the floor and seeing the picture of mortified penguin, a timer will begin. Go back the air duct which you came and this time take a left away from the way you came in and drop down to the exit area where you will see a white van. The game will pick up from there to say " mission complete ".

You go through the vent that you came in and wait until that guy says you will be exracted.Go to the end of the vent go down the hole look forword and there is the point.

You need to kill all three guys that are trying to get into the vault. After you've done this get to the entrance of the vault in the crawl space. Pull out you rifle and shoot the valve handle where they were standing, this will stop the flow of steam coming down the other part of the crawl space. Go to the end of the crawl space, drop down, and head towards the van. Done