Lady Phoenix was shocked that this loser had panicked. He had panicked because he was afraid and she did not want to deal with a coward at all. So she had to make him learn to deal with his fear and he had to stay motivated. That is why she chose to trample him, inflict pain on him and humiliate him. When he learned to contain those, he would be ready.
Lady Phoenix and her friend mistress Delvia wanted to do something to do this guy because he had abused their generosity. The mistresses were pissed at him and they had to teach him a lesson. That is why they used their bbw bodies and weights to trample and stomp on him. In no time, he was in pain and he was begging them for mercy but they ignored him and taught him a lesson.