At the end of the poem "Ai Jiang Tou", the Tatars on horseback covered the town with dust in the yellow twilight. What role did they play?

In the autumn of the first year of Tang Suzong to Germany (756), Du Fu left Zhangzhou for Tang Suzong, which had just acceded to the throne. He was captured by the rebels of the Anshi Rebellion and taken to occupied Chang 'an (Du Fu's "Spring Hope" was written at this time). The following spring, the poet walked along Qujiang in the southeast of Chang 'an, and was deeply moved by the scene before him. He wrote this song "Love the River Head". In poetry, the poet is moved by the scene, and his sadness is beyond words. The whole poem is as follows:

Shaoling night swallowed and began to cry. I quietly walked down the winding river like a shadow of spring. There are thousands of palaces on the shore and new branches of willows. Who are you green for? ? I remember the colorful flags floating from the South Garden, which was full of colors. The first lady of the kingdom, from the Sun Palace, waited on the emperor's royal chariot. The cavalry in front of them were all holding bows and arrows, and discerning horses were chewing gold. An archer, chest up, through the clouds, smiling. Where are those perfect eyes and those pearly teeth? A blood-stained soul has no home and nowhere to go. The clear water flowed eastward, passing through the cracks in the watchtower, and there was no news of her! Compassionate people shed tears and hoped that she would be as eternal as rivers and flowers? Tatars on horseback, in the dim twilight, covered the town with dust. I fled to the south, but I was still staring at the throne in the north.

"Riding a Tatar, in the yellow twilight, the town was covered with dust, and I fled to the south, but I was still staring at the throne in the north." Poets render their deep feelings and confused thoughts by describing their own behaviors and actions. The previous sentence "Go to Tatar, in the dim twilight, cloud the town with dust" pushed the atmosphere of high pressure and terror to a climax, and put an end to the initial "swallowing tears" and "sneaking around". At dusk, in order to guard against the resistance of the people, the rebels went out one after another, so that the dust flew over the whole Chang' an city. Then the next sentence, "I fled south, but I lingered on the throne of the northern dynasty", an absent-minded poet wanted to return to his residence in the south of Chang 'an, but ended up in the north. The poet expressed his great inner grief by being upset and unable to tell the north from the south. It can be said that in the end, the poet not only has implicit images and rich meanings, but also secretly takes care of "Shaoling's old weeping at night, like me stealing a spring shadow downstream", thus strengthening the expression of emotions.