yadā sanharate chāyaṁ kūrmo ’ṅgānīva sarvaśhaḥ
indriyāṇīndriyārthebhyas tasya prajñā pratiṣhṭhitā || 58||

My Understanding : The tortoise is unique in that its body parts are very sensitive, yet it protects itself by retreating into its shell when faced with adverse conditions. Similarly, people with a steady intellect control their senses in response to challenging situations, guarding their inner peace just as the tortoise protects itself.