Come on its not Subbuteo. It was a split second thing. If anyone needs to communicate to Duffy that he has let his man in behind its just as much O'Shea's role.
As a keeper I'd often glance at my back 4 to see if they were OK, then look out to the wings at the ball and by the time that has all happened the forward has lost his marker.
I'm not going big on Randolph here. The least of his errors was communication I'd say. He isn't a line keeper like Shay. That's what you get with a keeper who sees it as his job to take dangerous crosses. Yes it was a split second misjudgment but I still think he'd had had his work cut out to save a free header from 8 yards.
Every goal ever scored has been avoidable in hindsight.