Instead of using her rope, she attacked directly with her fists two or three times.
If he tried to block those blows with his arm, the arm would explode. Thor forcibly twisted his body around to avoid the blows. Every one of his actions just about tore the joints of his arms and legs to pieces. He was keeping his movements to the bare minimum, but the human body was not made to function at those speeds.

Toaru Majutsu no Index New Testament vol.6 ch.7 pt.7