Dierdorf was so wrong. That safety on the botched punt snap was actually the best thing that could have happened to the Pats on that play.
Was it the best, or was it the second best? It looked like Allen was trying to throw a pass when he fumbled the ball. Wouldn't the smart play have been for him to throw that pass, and have it fall incomplete? Then there would be no safety, but since it was an incomplete pass on 4th down, the Colts would take over at the line of scrimmage (which, IIRC, was somewhere around midfield), not on the Pats' 2 yard line.
I don't remember exactly where the line of scrimmage was, but depending on where it was, that might have been better than giving Indy 2 free points. (Though awfully difficult to execute. Allen would have to throw it in the direction of one of his teammates to avoid an intentional grounding penalty, and he'd have to trust that player to be smart enough to let it fall to the ground.)
But either way, giving Indy possession on the NE 2 yard line would have been the worst scenario, so Dierdorf was absolutely wrong on that.