I wasn't aware that they'd actually filmed Sarah driving herself. My theory (http://roxybisquaint.livejournal.com/59377.html) had been that Kaliba implanted a tracking device, then drove her to the hospital and put her in the driver's seat. But that part of my theory kind of got blown in "To The Lighthouse" when Sarah flashed to Winston when she found out about the tracking device. I still have a hard time believing a woman who was unconscious woke up and drove herself. I guess she's just that much of a badass ;)