Well, the "kiss" account puts JY responsible for her own demise in several ways that he may think offer him "sympathy" with a jury.
First, he was just innocently walking by...it's JY's fault that he even entered the flat. My version puts his presence in the flat squarely on him. He had no invitation and no right!
Secondly, his version has JY flirting and therefore, his his mind, inviting his action next (the kiss.) My version has JY startled with a GENUINE reason to scream and be fearful. In this latter scenario, VT bears responsibility alone for her response.
Likewise, his version makes JY sound like an hysteric...again shifting responsibility to her. No one would fault a woman screaming at finding her stranger-neighbor in her bedroom.
In his mind, his version has JY sharing the blame with him for the "accident." If he is caught in her flat and terrifies the poor woman, it is both humiliating to him...and shifts the responsibility for events that transpired next, entirely on him.
VT feels sorry for himself. He wants JY to shoulder some blame for HIS predicament. Hence, his "story."