Punch him in the balls!

You weren't going down so easily you summon all your strength and give your most epic punch straight into his go-nads and sprint away.

"AHHHHHH!" He screams like a girl and falls over. "OOHH~~" he moans, as you leave you can still hear his girl-ish squeals. You giggle as you realize that was the same sound you heard on the phone and hurriedly try to escape the place by leaving the library room.