There the level below the train. Recently travelators have been installed to reduce the amount of walking needed.

If it hasn't already, the signage should be improved to make this option easy to find. It's always been open to all, but until recently passengers have been discouraged to use it.

Is it quicker than the train? Depends on your walking speed, if you've just missed a train I'd say it's quicker. If it's quiet and a train is due then the train is the better option. If it's crowded I always take the walking option.