Time: Various
Frequency: Always
World name: Balmung
Character name: Ginkgo Biloba
Class/Level: Machinist / 60
Party or solo: Both
Area and coordinates: First in Void Ark then replicated afterwards several times in Dravanian Hinterlands.
Steps:
1. Activate Promotion immediately before turret hits 0 HP

The TP/MP restoration effect doesn't persist, but Promotion does and continues to drain MP until you redeploy a turret and use Promotion again to turn it off.