Jack followed the man he hypnotized from the distance to enjoy the sight of the intruders killing each other. However, the longer he followed the man's tail, they passed through dead body lying.
The time Jack saw another body lying on the ground, Jack stopped as he squatted down to check his pulse. The person shed no blood, and Jack didn't hesitate if the person was just faking it or not. After all, with the person's position lying face front, he would be at a disadvantage, regardless.
Jack checked his pulse to confirm his initial thought. After several seconds, he tossed the arm away as he has no pulse. Since the man she no blood unlike the three bodies he passed by, there was only a person who would kill a person with less blood being shed as possible: REX.
