One more thought.

You could check in for your NW flight using the online check in (up to 24 hours before your flight). Then, tell the shuttle driver to drop you by the doors opposite the escalators at T2(or tell him Virgin). This will save you the time at the e-kiosk, and the walk from the kiosk to the escalators (perhaps 100 yards). This may save you only 3-4 minutes, but it could be helpful if you are trying to hurry.