It looked to me like the corner dropped like he was going to cover the deep third and then came up when he saw Beasley run the out. Beas saw him come up out of the corner of his eye so rather then running into the DB he settled in the gap. If Beasley is telling the truth and he had no option to cut the route short then Romo never should've thrown the ball to him and hit the vertical receiver outside over the corner instead. Romo has been going to Beasley on those quick outs late in the 4th quarter in numerous games now and it has just caught up with Romo not reading it and just throwing it.
That's my two cents anyways.