The convent of the nuns is a baroque labyrinth like Ivan's palace. Note the similarities in the doors which Vanessa Redgrave has to squeeze through. Eisenstein, and then Russell do this to draw attention to the set design.
The procession of the Moscovites to Ivan to ask him back to Moscow is a visual copy of the procession of the village people to the frozen ship asking for the body of Elsalill. Ivan's pose resembles that of the ship's captain.
