Select Kung Lao because each of his throws result in eighteen hits. After you remove a Boss's armor, dash or run to him, and perform a throw, then repeat the process. Alternately, block and punish Boss attacks. For example, when countering Quan Chi's Teleport, upper-block, then punish with a throw. Choose the Full Auto version of Jacqui Briggs. Use her Hand Cannon move to remove a Boss's armor and inflict five hits each if it reaches a non-blocking Boss. Repeat it until time expires or you die. Her X-Ray also results in fifteen hits.