"Dinner and a movie" = cutesy term for a date. The phrase "a night on the town" also popped into my head, and that fits with the preview vidcaps we've been seeing. Looks like this is the individual RC where the winner and their designated choice get to leave the M&M camp for an evening. May be male and female, maybe not -- we have no information to lead us one way or the other on that. This will be one of the highlights of the show, since it should offer a nice change of pace from the typical Smelly-People-Sitting-Around-Whining-In-The-Camp episode.

"And a betrayal" = Is this tied into the activities of the RC? Maybe. Or maybe, it's just a reference to what happens at some other point in the episode. We've got two possible betrayals that we know about right now: 1) old Boran joins old Samburu or 2) someone gives Lex the information he needs to discover that Teresa voted for him. Since this will provide significant information about the direction for future episodes (Pagoning? new alliances?), this is highlighted in the episode title.

I don't think that the way the title is worded (Dinner, Movie, and a Betrayal) means that all of these are tied together as one incident (the RC). I think it's just a short and cutesy way to tie together the two main plots of the evening.