While Luke was struggling to reach Violet, the force behind the skin piercing gales increased tremendously. His body began to lose ground against the wind and he was soon knocked off his feet before crashing into several objects before hitting the wall with enough force to knock the wind out of him.
Jack had turned his limiter off and was operating at full mana capacity. He was in no position to control the force of the wind that he was manipulating. As such, Luke wasn't able to retain his senses after slamming into various obstacles and fell groggily to the ground as he verged on the edge of unconsciousness.
Violet was shocked because she hadn't expected that Jack had been holding back against her. Just the force of the gale was more powerful than that wrist blade he had used against her. If he had used such a power at the beginning of the fight with her, she would not have survived until Luke arrived to save her from that final blow.
