I agree Rose! I have always said that. If you watch really closely, Casey freezes with her jaw a little dropped and appears to be bracing herself for the worst, almost as if for a split second, she thinks she has been caught. She looks absolutely terrified she then recovers with a "Surprise Surprise" and shortly thereafter basically has her temper tantrum. It happens in a split second but it speaks volumes. I am so glad someone else noticed it.
That tiny little moment, from the first time I saw it, solidified for me long ago, that she drowned Caylee in the pool.
She is like Keyser Soze and always always takes bits of truth around her and infuses them in her lies. Every single time. She replaced George with herself when telling the story of how he "killed" Caylee during a supposed horrific act.
In Jeff's book, he goes over Casey's statement to Jose about that. In it, she is very descriptive about what George's clothing looked like after he supposedly drowned Caylee in the pool.
She said his clothes were wet and splashed with water on his shirt and waistband, kind of like hers probably were after she did what she did. It was eerie.
By the way... I noticed recently that Casey also used her "Surprise Surprise" line in one of her fake Universal emails to herself that were supposedly from her boss.
I believe now more than ever that Caylee died in that pool, and as most of us have always known, it was no accident.