Canto 1, Chapter 7, Text 18
tam āpatantaṁ sa vilakṣya dūrāt
kumāra-hodvigna-manā rathena
parādravat prāṇa-parīpsur urvyāṁ
yāvad-gamaṁ rudra-bhayād yathā kaḥ
Aśvatthāmā, the murderer of the princes, seeing from a great distance Arjuna coming at him with great speed, fled in his chariot, panic stricken, just to save his life, as Brahmā fled in fear from Śiva