the one thing that isn't up for debate — "This is a thing I do…"
This is a thing I do know. They can't kick you out.
Context
Where Gately finally has solid ground, and it's not an argument: told his patient face makes Day want to scream in meetings, Gately says so scream — they can't kick you out. Against all of Day's unanswerable logic, the one thing the staffer knows for certain is the Program's single unconditional guarantee: your doubt, your rage, your erudite contempt cannot get you expelled, the door stays open no matter how badly you behave inside it. It's the warmest beat in the debate and the most load-bearing — belonging offered as a fact rather than won as a point, the thing the horror most needs to hear.