Can I ask a burning question I have about the 2 way mirror? Sirius gave that to harry saying if ever he needed to talk to him, he could use it. Harry was, IIRC, feeling a bit sensitive at the time and vows to himself that he won't call on Sirius and puts the mirror at the bottom of his trunk.
Later on, there is the big moment when he has the vision that Sirius is injured in the Department of Mysteries. Hermione persuades him to check to see if Sirius is at Grimmauld Place and he goes to Umbridge's office and talks to Kreacher in the fireplace.
Sorry if I am missing something here, but why did he not use the mirror then? Surely that way he would have been sure to get Sirius (who was only actually upstairs tending to Buckbeak) rather than Krecher who misled him and led them all to their bug mistake of going to the Department of Mysteries. Obviously the plot would have been messed up at that point so I assumed JKR had Harry forget about the mirror so he would have to use the less reliable method of the fireplace.
but then, at the very end of the book, harry does find the mirror at the bottom of his trunk. He tries to use it to contact Sirius even though he is now dead. I assumed at this point he would realise his huge mistake in throwing the mirror to the bottom of his trunk and forgetting about it, but no, there is no moment of realisation or regret. I found this very odd. It made me wonder what the 2 way mirror was for. I still think it would have been far more realistic for Harry to have been doubly mortified, not only at being instrumental in causing Sirius' death, but also in realising that it could all have been prevented if his pride had not got the better of him.
What does anyone else think?