At 1.2 million square feet, the Amazon Fulfillment Center (FC) in Middletown, Delaware is the size of 21 football fields and employs roughly 2,500 full-time employees, swelling to almost 7,000 employees for the holiday season. Codified as PHL-7, it’s one of 75 Amazon shipping complexes spread across the US, but the only one in the northeast open to the public. Last Friday the Tech Club at Wharton arranged a tour of the Delaware FC to walk us through a product’s lifecycle in the center from when it arrives…