Dave and Jenna are wearing their buffs which they would have been required to wear at an RC. Since the buffs are the original tribe colors, the simplest explanantion is that a separate tribes RC where the top man and the top woman (either winning separately or as a team) go on a reward.This is about the time that MB would want to start breaking down the gender based tribal barriers. What better way to do that than getting one member from each tribe out alone... clean them up a little... and let nature run its course.
Good for ratings and it may foment a little distrust in the tribes waiting at home.
I'm thinking that is not a post merge/swap reward date...
Nor is it a traibal ambassadors meeting...
I think that is a pre merge/swap reward date...
The twist is simply that one member of each tribe goes on a shared reward. The tribes will, however, remain unmerged and unswapped in EP5.
Maybe this pattern of getting the tribes intermingling on a one on one basis will continue in EP6 and then a conventional merge at 10 members occurs at EP7.