The pattern is teaching the reader to distrust every Krieg promise for the rest of the arc. Forward-payoffs:
Krieg’s negotiations with the cooks (Ch. 47+)
Krieg’s surrender beat with Mihawk (Ch. 50)
Krieg’s deals with Gin (Ch. 65-68)
Why this matters
The chapter executes a single-chapter setup-payoff loop for the villain-duplicity beat — unusual for Oda, who normally distributes setup-payoff across arcs. The one-page-wide setup-payoff here is a reader-training exercise: the chapter is establishing how to read every later Krieg promise. Pattern-naming candidate: the within-chapter villain-tell loop.