After retreating from the wounded Fifth Officer, Jiang Fei put away his sword and relaxed. The reason he did that was simple. He did not want to kill despite it being so easy for him, since the enemy were the Valsalrians. Moreover, the Fifth Officer was but a small fry. There was still the top brass, Commander Alexis he would have to face. Jiang Fei was almost certain that he could not defeat Alexis and even if he did, there would definitely be other Commanders ready to barge in.
Why cultivate enmity when he could use this situation to cultivate fear. He could give an impression to the Valsalrians that Earth was not just some random planet in a random galaxy of a random quadrant of space. Earth had fighters, strong fighters such as Jiang Fei to defend it.