Upon watching the replay, Randall had Woodhead in the flat and didn't come off until he read Rivers eyes and Rivers started to throw. Randall would have broken it up if it was thrown to Woodhead.
That's the way I see it.
Randall picked up Woodhead off the line...covered. It looks like Rivers looked to Woodhead first, saw him covered, and progressed to Gates. As soon as Rivers looked off him Randall jumped to Gates. I think it is fair to say Randall did not leave a man he had covered as some random decision. He read something, and that something was Rivers eyes, maybe his stance too when he reset his feet.
What ensued was a little interesting. Matthews, who had his back to the play, turns to Hyde and points at Woodhead. Hyde points behind himself as if to say, "not my man, talk to him." Randall steps forward, gesturing to Matthews in a way that does not express apology.
Rivers may have been fooled by that play. On the 4th. down it was same route, same coverage and Randall did not come off Woodhead...because Rivers did not look him off.
Could Rivers have come off Gates and come back to the wide open Woodhead? Sure. But players take calculated risks, whether based on film study or experience or instincts. What distinguishes good players is they are right a lot more often than wrong. Randall? So far so good. For that one play, the proof was in the
putting.