He Died
One of the things that Rui had prepared the most was a counter to the Maneater. He knew that she was definitely the biggest individual threat to him. In fact, if they had a random encounter, Rui definitely wasn't confident he could defeat her.
He had spent the most amount of time developing a powerful counter to her.
The solution was more simple than he had expected, however.
He simply had to hypnotize his perception of her.
Over the two weeks that he spent preparing himself to fight her, he hypnotized himself to alter his perception of her.
It was a hypnosis technique that he designed to be passively triggered by her appearance. His mind would warp her beautiful appearance into the ugliest woman he could possibly imagine.
This would curb her hypnosis and stop any visual psychological manipulation.