Shi Lang was dodging the attacks thrown at him by Jane at high speed, her fists were akin to a blur, and Jane's aggressive behavior made her target all the attacks on his vitals. Sometimes the fist was only missing his forehead by a mere inch.
Jane was not simply slogging at him, her mind was calm, yes, she was not an idiot with rage and revenge. She was a technician, these points were taught to the whole class by Shi Lang that one must maintain absolute calm as soon as they enter battle or the rage will consume them instead. The surprising fact was that Jane's skills were not bad, she was keeping up with her practice and maintaining what she learned in school.
