This is yet another thing Cassandra Clare blatantly stole from Harry Potter.
Why does Cassandra Clare keep doing this? Seriously, Clare was a part of the Harry Potter fandom for a very long time, and she had to know how crazily devoted the fandom is.She had to have known that people would immediately pick ou the uncanny similarities between the two books. Yet again, Clare kept this scene in the book anyway. I will never understand the thought process of Clare and her editors!
Also, Jace looking into the mirror for any hope to see Valentine is completely ridiculous. First off, it’s been days since their final confrontation with Valentine and logically he should be long gone by now. I also want to point out how completely absurd it is for Jace to still believe that Valentine really hid the cup in Idris. I would also like to point out yet again that Valentine is a self-confessed habitual liar and I personally would take anything he had to say with a grain of salt.