The Adhesive Duck Deficiency - S3-E8
Corrected entry: There is no way Sheldon would have been able to hear Penny call him for help as as he did, through four closed doors, two rooms and a hallway.
The Adhesive Duck Deficiency - S3-E8
Corrected entry: When Penny and Sheldon get into the car to drive to the hospital, she makes the remark, "You do have a learner's permit, right?" He answers yes and explains he has logged several simulation hours which ended badly. She already knows he has a learner's permit and about the simulations, since in season 2, "The Euclid Alternative," she was with him at the DMV when he got the permit and stood beside him during the simulation, actually hitting him in the face with a pillow to mimic an airbag when he crashed.
Correction: Actually, after Sheldon said that it was the first time driving an actual vehicle, she said "you do have 'your' learners permit, right?" It was an indirect reference to the fact that (approx) a year had passed (a season for us viewers) and he had not stepped into an actual vehicle. Penny has been known to be sarcastic from time to time.
Correction: Sheldon's 'Vulcan hearing' is an important plot device, used in a number of episodes for comic effect. This is one of them. In another episode, Leonard says he can hear her toilet flush, so the apartments clearly aren't very soundproof.