Mbh 7.29.2a

“Sanjaya said, ‘[Although thy troops were broken], yet, O monarch, many foremost of heroes in the world, inspired by the desire of doing good to thy son and of maintaining their own reputation, followed Drona. In that dreadful pass, they fearlessly followed their commander, achieving meritorious feats against the Pandava troops with weapons upraised, and Yudhishthira within accessible distance.[58] Taking advantage of an error of Bhimasena of great energy and of heroic Satyaki and Dhrishtadyumna, O monarch, the Kuru leaders fell upon the Pandava Army.[59] The Panchalas urged their troops, saying, “Drona, Drona!” Thy sons, however, urged all the Kurus, saying, “Let not Drona be slain. Let not Drona be slain!” One side saying, “Slay Drona”, “Slay Drona,” and the other saying, “Let not Drona be slain,” “Let not Drona be slain,” the Kurus and the Pandavas seemed to gamble, making Drona their stake. Dhrishtadyumna, the prince of the Panchalas, proceeded to the side of all those Panchala car-warriors whom Drona sought to crush. Thus no rule was observed as to the antagonist one might select for battling with him. The strife became dreadful. Heroes encountered heroes, uttering loud shouts. Their foes could not make the Pandavas tremble. On the other hand, recollecting all their woes, the latter made the ranks of their enemies tremble. Though possessed of modesty, yet excited with rage and vindictiveness, and urged by energy and might, they approached that dreadful battle, reckless of their very lives for slaying Drona. That encounter of heroes of immeasurable energy, sporting in fierce battle making life itself the stake, resembled the collision of iron against adamant. The oldest men even could not recollect whether they had seen or heard of a battle as fierce as that which took place on this occasion. The earth in that encounter, marked with great carnage and afflicted with the weight of that vast host, began to tremble.