Su Chuanyun and the three others left the Xinghe Squad and joined the main battlefield. They couldn't catch up with Ji Xinghe, and even if they could, they wouldn't be able to exert the same intimidating effect as Ji Xinghe.
Ji Xinghe didn't stop them because it was their choice, their responsibility and obligation.
Compared to Ji Xinghe who could only float outside the battle, Su Chuanyun and the three others were able to integrate well into the Federal Mech formation, and they could cooperate with the soldiers responsible for support. With both sides suffering severe losses, the addition of these four had a significant impact.
As the first batch of mecha warriors directly incorporated into the Xinghe Squad by Base Five, they had participated in the Xinghe Squad's battles from its inception, which may be one of the reasons their strength greatly increased.