Aevia replaced her current state with her past and immediately pushed Mykel away with her third and fourth arms while she was still stronger than him. It was a close call or she would lose her power by Mykel since he would be strong enough to take her power away. She summoned more arms and used them to rip Mykel's hand off since they were no longer in an Eternal state.
The arms that Aevia summoned were moving so fast that Mykel couldn't dodge them all. Every time he got hit by it, he got his skin and flesh ripped off or his bones broken or pulled off. The arms could appear anywhere from thin air and could attack from every angle and at any moment.
Elena was lying on the ground, barely enduring the pain, and the worst part was she was the only one who took a huge toll on the fight between those two. She realized that every time Aevia hurt Mykel, she replaced herself with her past self.