It's very strange. KJ is back there in case there actually is a punt. Ivey engaged the guy, turned and ran with him for 5 yards, then stopped, almost like he heard a whistle (not defending him). There's no way he thought KJ was supposed to cover over the top; KJ isn't covering anybody; he's the return man. So, if it's a punt, Ivey has to block the guy for KJ. If it's not a punt, Ivey has to cover the guy. Either way, Ivey has a guy as his assignment, and he just stops on the play.
Think about this for a minute. If right before the play Coach Diaz said any of your names, and said "get in there against their gunner." You'd say, "but I'm not dressed out, and I'm old." He says "I don't care, the U needs you," he snaps his fingers and you're magically dressed out, "now get out there." You say to yourself, "dream come true", you line up, trying not to **** your pants because you don't want to ***** up, and without any instruction at all, nothing, no help from anyone, you would have run with the gunner (regardless of whether it's a punt or a pass to your guy or even a run by the punter).
So, as stupid as a call it would be for Diaz to put one of us in the game, does he really have to tell Ivey to stay with the gunner?