Kaze walked to the mansion housing the Lockheed University students.
The group was extremely valuable because he handpicked each for their minds, strengths, or looks. In particular, there were engineers among them that were critical to accomplish his goals.
Moreover, he intentionally let them experience the apocalypse, so they'd understand he saved their lives and what it was like to have desperate people demanding things of them.
Therefore, he planned to make them an elite force that sympathized with him and had the power to protect his interests once the news broke and he got flooded with thousands of requests from faction members blaming him for tricking them.
However, he first needed to solve the [serial killer] problem and [destroy his internal enemies] before they could do serious damage.
Otherwise, they'd run out screaming he was a serial killer, having the opposite effect, and they wouldn't help him.