Jack glides from his tiny room into the corridor, hoping Rose and the alien Doctor are asleep. They have quarters near the mysterious 'wardrobe' that provided Jack's new clothes. How big is the TARDIS? He can't investigate. The corridor access door is locked.
He drops to the floor, managing thirty press-ups before a female voice interrupts. "Jack? What'cha doing?"
Wha--? "Exercises. Running like hell doesn't tone all the muscles..."
"So use the gym."
"The Doctor didn't give you the grand tour? C'mon."
He doesn't tone any muscles that night, but his sense of wonder gets a serious workout.