a) Short stay car park, race top to bottom and beat the two squeaky lifts, it can be done going down, tough going upstairs though.
b) Travellator in the East Terminal (the one that goes past the stupid big wall photos and irritating quotes), almost impossible, no running allowed.
c) Exit escalator. This one is easy-peasy, great for beginners, only one go per flight so don't mess up.
You can do it at the airport and many other places, but not in John Lewis.