Jack was focusing on fast motions coupled with fast attacks. He was not aware of John's and Fierce Flame's assistance until one of Flame's arrows lodged onto the skull of a Fighter whose weapon was about to hit him. He glanced and saw the two atop.
Of the two, Fierce Flame was playing a better assist role, as her aims were more precise and swift. John knew his aim wasn't top-notch, however, he assisted Jack by targeting those who were not near Jack.
Instead, he played it smart by sweeping out those who were at death's door after getting attacked by Jack. Since Jack couldn't stay in one place long enough to finish the task, he gladly picked up the baton.
The rate by which the players in this outer half fell was higher compared to the ones that were trapped in the other half. However, even when they kept on losing people, not one of these from the outer half fled. Jack must admit he applauded these players' solidarity.