This scene is created in order that an audience can easily find out the evil spirit is Rokujo no Miyasudokoro, because she is the only person who has some story related to a broken carriage and she can have a noble attendant even though the rank of that attendant is not so high.
壊れた車に因縁を持ち、身分が低いとはいえ貴族をお供につれているとなれば、六条御息所しかありえないと観客にはわかるようにしている演出。