How can the withdrawal of Khalid ibn al-Walid with the army from the Battle of Mu'tah be reconciled with Allah Almighty's prohibition to believers from turning their backs to the disbelievers?

It has not been established that the Companions fled in defeat in the Battle of Mu'tah. Rather, the Prophet (peace be upon him) explicitly stated that victory was granted to them under the leadership of Khalid ibn al-Walid (may Allah be pleased with him). Scholars have differed on the meaning of this victory (fath): some hold that it was a triumph and a defeat for the polytheists, supported by the acquisition of spoils of war during the battle. Others believe that the victory meant Khalid (may Allah be pleased with him) was able to withdraw the army safely and in an organized manner to Medina, thereby avoiding the annihilation of the army. This withdrawal is not among the forbidden forms of flight; rather, it is permissible if it is for the purpose of joining a group of Muslims or the Imam, or if the enemy's numbers are many times greater than the Muslims' numbers, as was the case in the Battle of Mu'tah, where the Muslims were three thousand and the enemy was two hundred thousand.