Rennac's growl was audible through his helm as his punch hit and dented the bulkhead. OK, less force, more speed  and precision. He felt the overhead blow to his plating and was forced to one knee, balling up a fist and throwing a simple uppercut aimed right at his opponent's jaw. This was more focused on speed and less on force, likely only enough to kill or severely wound but would likely send him reeling.