Walter vs Cynthia Siren Scene

Okayyy so i played Walters route last time and this time im dating Vincent but chose Walter and Threxio to be women this time so Cynthia and Threxia…… but then the siren scene came and ????? Walter is in the water now??? What parallel universe is this??? And i noticed last playthrough that one of the sirens looked like Cynthia but I just figured because they are the same genetics that the siblings would look like them regardless but like… his name is Walter!!!!!!!!