Valmiki Ramayana Yuddha Kanda Sarga 17 Shloka 28

प्रविष्टहि: just as one who entered, अतर्कितः not to suspect, प्राप्तः one who appeared, शत्रुसैन्यम् enemy's army, शत्रुः enemy, अन्तरम् inside the hole, लब्ध्वा: having got access, उलूकः an owl, वायसानिव: like crows, निहन्यात् after killing.

"One who entered the enemy's camp and had access to come inside kills the enemies. It is like an owl killing many crows having entered the hole."