Of course sex is the main thing in his mind, have you never been 15 before? Also Kishimoto is kind of a dumb bitch, imagine talking so much about the guy you like and how kind he is when the kid is giving her a roof to live in and is pretty much the nly reason they finnished the mission on time. Kato is the best but for someone who is so good at handling tough delincuents he seems to lack that killer instinct, he's focused to much on surviving but not in actually finnishing the task.