On the other hand, what constitutes "working to prevent the publishing or airing of commentary" may well be fairly minimal. I can imagine a response of "we wrote to the publisher and asked them to not publish anything about you again." I certainly would be wary of any contract with a PR agent which imposed so little in the way of concrete obligations. Even if you are able to enforce this condition so as to require serious effort by the physician, they will be able to enforce a similarly burdensome condition on you in retaliation.