Estelle and Inez's Existence

Estelle does not think she exists without looking at herself in the mirror. We can infer, that in the past, Estelle looked in the mirror a lot, but now that she is in a room with two other people and nothing to see herself with, she does not trust her own judgement. She relies on Inez to be her mirror, but Inez merely takes advantage of this opportunity telling that she has a pimple when she actually does not. Inez, however, is the complete opposite and is always conscious of herself even without a mirror. She has always been aware of her existence and will not let anyone steal that.