meaning - Word or phrase for the moment/reason/motive you reveal to someone why you had acted a certain way prior to parting ways

A massive cliche in action movies (especially James Bond), but is there actually a word for that moment when the evil villain reveals their deadly plot to the action hero before (usually attempting and failing at) killing them?

If there is no word for this, is there a phrase for the "reason that this was done" i.e. if you asked the villain why they did it (apart from probably for personal satisfaction).

In a similar (but un-deadly scenario), is there a word/phrase/motive for the reason someone might feel like they wanted to tell someone (they wouldn't see again) why they had acted in a certain way prior to the final parting (i.e. telling them about past events during their final encounter)? e.g. "I acted like that because I really liked you and what you did made me feel bad at the time, and I felt like I needed to tell you because..." (is this even a good idea haha)