For a 250 lb DE, that's flat-out amazing.
I was actually impressed with TVondre Sweat, who tipped the scales at 366 lbs, but still ran a 5.27 40 time.
The linebackers especially had some nice 40 times, and for Liufau's 4.64 to be considered "middle of the pack," shows the athleticism in this year's draft crop.