They truly couldn't hold out any longer.
Moreover, the statement "The leader has escaped" might actually be true.
Many middle-ranking leaders had indeed not received any directives from Terrell, the supreme leader from the rear, for a long time. Even when they tried to inquire back, there was no news. Battlefield communications had been jammed by the 'Listener' who had advanced to the front, leaving only static on the radios; those who were sent back to ask in person either never returned, leaving it unclear whether they were dead or had deserted, or they came back as clueless as headless flies, having found nothing.
Under such circumstances, it was only natural that there would be a widespread occurrence of leaders from all levels surrendering starting with the Marauder Tribe.
The battle should be nearly over by now.
However, Perbov soon received news that wiped the smile from his face.