Absolutely love it, GREAT AND FANTASTIC Psycho reference! I would, however, in the interest of it looking more like a (9/11-ish) terrorist attack, love it even more if maybe someone should make this in an Azumanga Daioh version where Tomo is Konata sneaking in, Kagura is Kagami and Osaka is Tsukasa. And Yomi is Miyuki. Knives need to be heated to 100,000°F. Also their eyes and mouth on all three girls should really be red instead of yellowish-white to signify danger rather than a warning sign in either photo. Then it's wrapped up nicely imo.
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The quiet sneaking devils hand...Tatat!!There is no scene like this in the original anime.