Felix had clearly found Holt's weak spot. These guys were so desperate to extend their lives that they turned the entire Aquamarinus into a breeding ground. Obviously, they were terrified of death. As long as there was even the slightest chance of survival, they'd take it.
And sure enough, Holt immediately agreed. He pulled out some kind of device and flew off, clearly contacting his comrades.
"But even if I agreed," Holt said, "the three of us split up and searched in different directions. Ev