i think attention seeking behavior is oftentimes a cry for help, and even if someone may truly want to ctb, they may also be hoping that by telling someone things may get better. we're all desperate to escape our pain one way or another, and no matter how badly someone wants to ctb they may also be hoping that the pain can go away without having to resort to risky, drastic measures. after all, after a failed attempt, things only get worse. more than death, they may fear a failed attempt.
though, no matter the reason they tell someone they're going to/want to ctb, be it survival instinct or a cry for help or something else entirely, i don't think it inherently means they don't actually want to ctb.