Creon's reaction was fueled by his pride and his desire to maintain control. He was unwilling to show any leniency or compromise, and he was determined to make an example of Antigone to deter others from questioning his authority.
He refused to listen to Antigone's pleas for mercy and her arguments that she was acting in accordance with the laws of the gods and the dictates of her conscience. He was convinced that she was guilty and deserved to be punished, and he ordered her to be buried alive in a cave as punishment for her crime.
Creon's reaction to Antigone's actions ultimately led to his downfall and the destruction of his family. By refusing to show mercy and compromise, he alienated his people and lost the support of his son and wife, who both died as a result of his actions. His stubbornness and pride ultimately brought about his own ruin and the downfall of the city.