I'll defend the guys here. The more you see them the more you see why they missed.
The ball in from Proctor was rollong nicely and then took a huge bobble before it reached Rooney. He was timing his run to stroke it in but because of the bobble the ball reached him later and a ball which was rolling was suddenly in the air. He had a fraction of a second to adjust but wasn't quite able to. He was unlucky.
To be fair to Billy, there is some fault from Draper here, he took a bit of a heavy first touch and the ball he played across was firmer than it needed to be. Billy couldn't get to it with the favoured left foot and probably felt he had time to control it with his right and knock it in with his left but the touch was heavy and the defenders got back very quickly in numbers. Clearly he should have scored but having lost the initial chance he then did well to keep possession from three defenders and square it to Shinnie - who also probably should have scored but MacDonald did well to stick out a hand to clear.
Anyhow, there wouldn't be this debate if it wasn't for a fabulous ball over top by the much maligned Philip Roberts. The clip is worth watching just to enjoy that.