指が引っかかって、シャープペンはものすごい勢いで回転しながら里志の顔をかすめ、教室の隅まで吹っ飛んでいった。
落ち着いて立ち上がり、歩いてペンを拾い、何事もなかったかのように席に戻る。
So, if I were to see the following short past tense sentences in much the same context, I'd translate them like this,
指が引っかかった : My finger snagged.
回転しながら物をかすめる : It grazed against an object while spinning.
教室の隅まで吹っ飛んだ: It went flying off to to the corner of the room.
落ち着いてペンを拾った: I calmly picked up the pen.
何事もなかったかのように席に戻った: I returned to my seat as though nothing had happened.
吹っ飛ぶ is a slightly strange word that means to be propelled through the air by an outside force, and is used in all sorts of circumstances. It's often used for 'blown up' in translations, it's what happens when shutters or shingles are torn off by the wind, the causative of it is what Luffy of One Piece keeps threatening to do to his enemies. It's not used for controlled or deliberate flight, but for all kinds of cases of 'fly away', 'blow away', 'blow up'.
(Oh, well, ToriToribeさん answered much more directly already, but oh well, I'll leave this for posterity or something. I should mention though that there is a slight flaw in Toritoribeさん's excellent translation, in that it should be 'and flew away to the corner' because 'fly' conjugates irregularly in English.)