I know ramires should have scored but it wasnt a easy chance, when you are sliding on the ground, you might miss. Chelsea were far better side on the day but manu took their chances better.
Ball was dead. Anything after that can't be given as a penalty, hence why you never see shirt pulling before the corner being penalized, what ever the commentators think.
Because the ball was out of play before the tackle was made, or so at least the refs thinks....it was too difficult to say at the time and I can't see a replay just now
Example: If a keeper punches a player in the box after a shot has gone over the bar, the ref can send him off but because the incident happened when the ball is dead, all the ref can award is a goal kick. If however the ball was live when the keeper went and thumped the opposing no.9 then he could award a penalty...even if the ball was at the other end (btw I think something like that happened in the Championship or league 1 yesterday where a defender had a set to after the ball was cleared, red card and then a penalty to the other side)