四分律刪補隨機羯磨 2.201

2.201

(In the Vinaya: "If during the retreat, one's former wife, a grown maiden, a courtesan, or hidden treasures come to seduce and harass a bhikṣu; or if there are evil spirits, hostile bandits, poisonous insects, or ferocious beasts, or if one cannot obtain suitable medicine or attendants, [and the bhikṣu thinks,] 'If I stay here, it will surely cause difficulties for my pure conduct and my life'—the Buddha said: 'I permit him to depart.'" In accordance with the Vinayamātṛkā: "Moving one's retreat does not break the retreat." Other traditions do not contain text granting this allowance.)