If the low-level source beasts were lured by the temptation of the Beast King's blood, lost their cool, and become pure source beasts, then it would be understandable. However, these level 10 and above source beasts... They had a certain degree of resistance against the Beast King's blood. In addition, Lugh had already killed most of the source beasts around him. Those who were afraid of death would definitely not want to fight anymore.
After all, they were not like those low-level source beasts who charged at Lugh without thinking. From the start, they had been circling around Lugh blindly. They wanted to seize the opportunity to kill Lugh so that they could obtain the Beast King's blood and then escape. However, the current situation was that they could not obtain the Beast King's blood at all. Moreover, even if they did not want to kill Lugh, Lugh would still kill them.