This is a PERFECT description of Luke's "briefest moment of pure instinct" in TLJ:
"For a moment, the darkness in Luke’s own psyche flared to life, fanning the gentle flame of fear, and without thought or intention he moved on instinct to eliminate the threat before him. His training took hold to banish the demon, without the conscious realization that doing so would mean ending his nephew’s life."
- Skywalker: A Family At War by Kristen Baver