Premise: When I begin to sing, watch that window." He retreated hastily to a position on the main drive, and began in a deep roar, coupled with an unsteady gait, the following ditty: I am a Soldier A jolly British Soldier; You can see that I'm a Soldier by my feet … It had been a favourite on the gramophone in Tuppence's hospital days.
Hypothesis: He stayed firmly in place while he sang, his voice shrill and unwavering. 
Label: contradiction