All right, listen up, everyone!
I understand how everyone feels about being trapped on this island. I don't like it either. I'll be marching with you to address the wrongs that have been done to us.
But given the island's history, don't expect too great a response. In fact, it's very possible the people who we know as representative of the government on this island do not themselves have the power to leave it - that power may be held by their superiors, whom we have never even seen. Given their attitude toward us, they may not care what happens to anybody on this island. So demonstrate your discontent, but don't get too disappointed if it doesn't work to your satisfaction.
Moreover, do not let this march turn to violence. Everybody's angry and frustrated, but nobody has to get hurt, and if this does get out of hand, the people we'll be hurting are not the ones who deserve it. In fact, we are most likely to be fighting each other, and we have no more right to harm anybody on this island than the people we are protesting do. If we do that, we'll be playing right into their hands, and it'll do none of us any good.
I'm the Doctor, the oncoming storm! I will march with you, but if this gets out of control, I will have to stop you. I don't want to have to do that. But I'm not going to let anyone get hurt if I can help it - not now, not ever.