That's a quirky one but my interpretation of the rules is that in instances of unsporting behaviour or serious foul play, you get the card at the next stoppage regardless of whether the referee allows play on or not. There was no avoiding the red IMO.
The red is for 'denying a goal'. If Sunderland had scored there is no red card, just a yellow.
I had a look and the red should be for 'denying an obvious goalscoring opportunity', not the goal itself, so I believe my first guess about the red standing should be the way it would have been played out, if Phil Dowd had refereed evenly.
(Not saying he would, in general I find him to be shite).