Pinkwater Security is among several corporate security firms operating on Ganymede. In addition to general station policing duties, similar to Star Helix Security on Ceres, firms like Pinkwater are employed to protect the highly valuable agricultural operations being conducted on the moon.
It is unclear at what point Wendell came into the employ of the firm or gets stationed on Ganymede, or even when his team came together. While his previous experience and training is unknown, he's described as being a skilled and professional soldier.
Following the Ganymede Incident, the environmental systems of the colony were degrading rapidly and the Agricultural firms were transporting as much of their product off the moon as they could to avoid any potential losses, resulting in a local food shortage. Those concerns, combined with the threat of further armed conflict, resulted in a mass exodus from Ganymede. At some point during these events, Wendell and his team were terminated from Pinkwater.
Without employment with corporate security, Wendell and his team had no more access to off-world transportation than any other colonist. They began an impromptu protection racket to sustain themselves in the meantime. It was while running this racket that they ran into Holden, Amos, and Prax. Recognizing their potential usefelness, Wendell and his team are recruited to aid in the recovery of Prax's daughter in exchange for transportation offworld. During the effort, three of Wendell's colleagues are killed, and while no children are found alive, Holden honors their deal and gives them the ship he snuck onto Ganymede with, the Weeping Somnambulist.