Factual error: Illya leaps onto the rope in the monastery tower, causing the bell to ring. After sliding down the rope to the floor, he then identifies the tone as "B Major 7th." But the musically-literate Illya should know better. B Major 7th is a chord (B, D-sharp, F-sharp, A-sharp), not a single note.
Factual error: Though he's tied up at the time, Solo somehow calls Illya on the pen communicator in his pocket. This leaves us to wonder just how he managed to uncap the pen, extend the antenna and "dial" the frequency (all of which was always necessary before) without the use of his hands.