Source text
وَبِوُقُوعِ خِنْزِيرٍ وَلَوْ خَرَجَ حَيًّا وَلَمْ يُصِبْ فَمُهُ الْمَاءَ
• If a pig falls into the small well, complete drainage is required even if it comes out alive and its mouth did not touch the water.
• The text treats this as a special case because of the pig's legal impurity.