Passage: On the basis of this information, Scipio elaborated his plan for the battle. He knew that the Carthaginian preparations to attack Castra Cornelia were continuing, and with the first signs of the spring he launched a preemptive strike. The ancient authors provide two versions of what happened. According to Livy and Polybius, Scipio placed a detachment (2,000 strong) on a hill overlooking Utica so as to deceive the enemy’s scouts that he was preparing to attack the city. Another small detachment was left to guard the Roman camp against possible attack from the city’s defenders. The main forces marched at night, more than 10 kilometers, and reached the camps of Hasdrubal and Syphax before dawn. Scipio separated the army in two halves and ordered Laelius and Massinissa’s Numidians to set fire and destroy Syphax's camp. Laelius and Massinissa left Syphax's warriors almost no chance to escape, as they were caught sleeping and utterly unprepared. The flames that started from the huts outside the palisades spread easily and engulfed the whole camp. All the exits were blockaded by the Romans, and numbers of unarmed soldiers were slaughtered; others were caught by the flames, as well as many pack animals, or were trampled to death at the gates. The same happened with the army of Hasdrubal. Its soldiers were awakened by the news that the neighbouring camp was ignited, and some of them rushed to help the Numidians without arms, thinking that the flames were the result of an accident. Scipio waited for this moment of confusion to attack with his part of the Roman army. The Carthaginians could not offer any organized resistance and were crushed. Only their general (as well as Syphax), with a small body of troops, managed to escape.

Question: What did the detachment overlook?
Utica