Yeah me too. But I understand why she did what she did and respect her for her choice to not do that as well.
Well I read this deleted scene from one of the リンク on this spot,
link (it's also on the mortal instruments website, but the link on the site wasn't working for me - so I link あなた to the one of this spot) and it was a deleted prologue to City of BONES（ボーンズ）-骨は語る- which was cut out. It's seems like Jace dreamt of Clary before they got to Pandemonium that night so I guess his reaction was surprise when he first saw her. But that would probably be the most likely reaction whether または not he dreamt of her the night before, since she could see through their glamour and they didn't expect someone to interrupt them.
