What is the consequence of an oath forbidding movement between two women located on different levels connected by a ladder?

Primary text

If a man has two wives, one in the upper room and one in the lower room, and he swears, 'She shall neither ascend to this one (the upper wife) nor descend to the other (the lower wife),' the lower wife may ascend and the upper wife may descend. Subsequently, the husband may descend or ascend as he wishes.