George Vander Linde tapped a code into the emergency room’s automated medicine cabinet. A drawer slid open and he flipped the lid, but found nothing inside.

Elon Musk has few days to make good on his pledge that Tesla will be pumping out 5,000 Model 3 sedans a week by the end of the month. If he succeeds, it may be thanks to the curious structure outside the company’s factory. It’s a tent the size of two football fields that Musk calls “pretty sweet” and that manufacturing experts deride as, basically, nuts.