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She used it aboard a Mondasian colony ship during the Battle of Floor 0507. The activation controls were located at the handle end opposite the emitter at the tip. Missy had a tendency to dance with it when hearing music. It had multiple uses, namely how Missy used her umbrella to locate and call up a lift on board the Mondasian colony ship, (TV: World Enough and Time / The Doctor Falls) locate the hidden lifts and shuttles found on Floor 0507, lock said lifts to stay on the desired floor, close a metal door several feet away and could combine with the Twelfth Doctor's sonic screwdriver to create a barrier to hold a fully evolved Cyberman back while the Master (using his laser screwdriver) and a cyber-converted Bill Potts disabled it. The umbrella could also be used as an effective melee weapon; Missy used it to strike the Doctor to the floor shortly after he gained an advantage over her younger self, and to briefly knock the Master out with a blow to the head. (TV: The Doctor Falls)
Her successor gave up using both this tool and the multipurpose device in favour of returning to wielding a tissue compression eliminator.