I walked this route from Penn to Moynihan today, as I'd never done it before. It's pretty far away from the Met Lounge so unless they call the train 5-7 minutes earlier than they do for the rest of the station, by the time you go down the escalator and make your way across the station and down to the west concourse, you're really not beating the line, you're just walking at the same time the line is standing and inching.