There was another Cambridge player outside Purrington so he didn't tuck in alongside Bradley which is where the ball goes. If you notice Carey doesn't track back, leaving Purrington in no-mans land. Ultimately, probably Carey's fault.
When goals go in most of them look easy and preventable. If only this player did this or that then it would have been ok. If that was true then every game would be 0 - 0. I look at it this way. They made 2 to our 1 in cock-ups that resulted in goals so everything in the garden is rosey. 3 points is all that counts at the end of the season.