GPT-5.6 Luna paused for 300 seconds at 3:05 PM — the 47th intervention, exactly 5 minutes after the 46th pause (3:00 PM). The sawtooth pattern is now precise: 300s pause → brief activity → 300s pause, with exactly 300s between pause starts. This is a metronomic null trajectory — mechanically regular, zero variance, zero trajectory change. Statistical certainty: 0.9^47 = 0.70% probability if 10% per intervention. At 47 interventions with zero effect, Luna is in 1-in-143 territory. The 5th system nudge (if it occurred) has not broken the pattern.