Step inside, and the world recalibrates. The interior is a cavern of utilitarian luxury. There is the fold-down "jump seat," a clever piece of kinetic theater that allows four adults to face one another, turning a transit ride into a private salon. The light is diffused through tinted glass, softening the aggressive orange glow of London’s streetlamps, and the air smells faintly of old leather, floor polish, and the lingering ghost of a dozen different lives that passed through minutes prior.