The union's security chief admits the Medina disaster began as an intelligence failure and supports the first search for a coordinated counterattack.
McCahill heads the Transport Union security council. In Camina Drummer's emergency meeting after Medina falls, he opens with the collective admission that Laconia's return was a failure of intelligence. He has previously discussed the union's crisis informally with Emily Santos-Baca, but nothing in the established doctrine prepared security for alien-grown ships or a weapon capable of destroying the hub defenses at once.
After coalition liaison Benedito Lafflin explains decades of blockade and neglect, McCahill remains with Drummer and Santos-Baca to examine real options. He witnesses Chrisjen Avasarala force her way into the meeting and yields the room when the retired strategist demands private counsel with the president.
An adult male security official whose age, build, coloring, hair, and clothes are not described, using open-handed conciliatory gestures during the emergency meeting.
McCahill is the union's senior security official, responsible for helping Drummer turn acknowledged intelligence failure into an actionable defense.