This girl was jealous of mistress Gaia and tried to imitate whatever she did. She did not like that very much. She would have preferred the girl ask her for help and she would have gladly helped instead of her being jealous and also trying to imitate her. So she helped her by punishing her which she did using her breath play fetish. She was choked and that taught her a lesson.
Goddess Lena is one of those people who dominate for fun and that is what she did to this slave. He had not made any mistake but he found himself choking and gasping for air just because goddess Lena felt like trying it out and she chose to do it to him. She was doing all of this for fun which pissed him even more as he did not have to go through that.