Six feet above contradiction?

The pulpit in the peninsular church. Not sure why it has a door behind it. To stop the preacher escaping? Or to stop them getting up there in the first place? Or to let him/her duck behind to avoid missiles? Or to stop draughts (the congregation's favoured suggestion). Anyway, there it is, a big mickle mock gothic door, at the top of the stairs up through the chancel arch...