He should keep small outlets in his walls for firing guns from his fort, and carefully make arrangements for their defence like that of the greater gates.
संकटद्वारकाणि स्युरुच्छ्वासार्थं पुरस्य च। तेषां च द्वारवद् गुप्तिः कार्या सर्वात्मना भवेत्॥