Valmiki Ramayana Kishkindha Kanda Sarga 51 Shloka 2

क्षुत्पिपासापरिश्रान्ताः exhausted with hunger and thirst, सर्वशः by all means, परिखिन्नाश्च fatigued, तिमिरसंवृतम् filled with darkness, इदम् this, बिलम् cave, सहसा all at once, प्रविष्टाः entered.

'We are exhausted with thirst and hunger. We are fatigued. (Hence) we entered this dark cave all at once(without waiting for permission).