Piglins that are scared by soul fire will run away from the soul fire like they are supposed to. If other soul fire is around them, they will run directly into the soul fire to escape another soul fire.
- Create an enclosed chamber like the one in the picture
- Start a soul fire on each corner
- Spawn a Piglin
The Piglin runs back and forth into both fires to escape the other, and the piglin eventually dies.
MC-172209 Non-fire resistant mobs don't try to avoid walking into fire