Demonstration Sheet for Updraft Principle

A thin, standard-sized scrap of printer paper torn from a stack or pocket, its edges slightly rumpled from quick handling. The Doctor holds it aloft, corners pinched between two fingers to display its lightness, the white surface unmarked except for faint creases running along its length. When released, it rises immediately on the heated air currents streaming from the cooling chamber's vents, drifting not with aimless drift but with purposeful upward motion—demonstrating the updraft like a miniature flag of escape. Codal and Taron watch with rapt concentration as it proves the feasibility of their escape plan, its performance convincing them despite the hostile Dalek presence closing in outside the chamber.