Matthew Stafford is an NFL quarterback, and generally not considered to be one of the more athletic ones. He ran a 4.81 40 at the Combine and the eye test would tell you he's had a few Little Caesars pizzas since then. But he runs hard.
Perrish Cox is an NFL cornerback, who is, among other things, responsible for tackling some of the quickest and most powerful humans on the planet. Matthew Stafford just absolutely ate Perrish Cox's soul. The official word hasn't come down yet but Cox will almost certainly be forced to retire after this game. Just a matter of waiting for the paperwork to process at this point.