we know freddie fought with kit and then made up with kit and then spent the night with him somewhere. we also know ben probably didn't notice, because his edit doesn't dwell on these moments. (editing this show must have been maddening. a performance in its own right, having to edit AS ben or meg or jaquie or whoever. jesus fucking christ, you know?) freddie seems happy enough in the morning to joke around with ben, and relaxed enough to be wearing kit's shirt, but she's still on her guard. she repositions herself as the king of the flat ("i let you have a taste of the forbidden fruit") mere moments after trying to convince ben to let her break a rule. she's not content to let the party fade into happy memories either, whether as a means of regaining control or linking her fight with kit to an overall pervasive bad vibe rather than personal conflict. she expresses concern over the flatmates splitting off during the party (despite the fact that they live together and can/do hang out all the time) and even brings up temp flatmate john's underage drinking (despite the fact that he spent most of the night quietly reading). she feels anxious, and maybe lonely in that anxiety since she isn't ready to open up to her boyfriend about it, and so she wants ben to be anxious too

we know ben seemed off during the party - because he was feeling lost without the camera? because he knows it's all temporary? because of the pressure of suddenly having no constraints on his relationship with beatrice? because he was resisting the siren song of the bath, his one true love? (kidding. mostly) ben's internal world is the biggest mystery throughout the show, and the night of balth's party is no different. we don't even get many shots of ben and bea. in most of their background appearances, they're sitting quietly together with their backs to the camera. same with that last scene, ben facing away from the camera at the sink. seems intentional. without ben being able to use the camera as a buffer, we get the clearest sense we've gotten so far that Something is off. but he's still shutting us (and bea) out, so we don't get any explicit dialogue addressing it. (sidebar: to me, this episode is jake's shining moment as an actor in this series. to be able to believably portray a bombastic character trying to act like their normal self and not quite getting there is deeply impressive)

peter's in a similar situation; he and balth both have consistently been using the rules to postpone thoughts and conversations they're not ready to have. peter especially is super back-and-forth on the rules. they're stupid, they're ridiculous, he's willing to break them to get what he wants (peter ends the show with the greatest number of punishments iirc) except for when he senses emotional vulnerability on the horizon (he's the first to speak up in opposition to the no-rules balthday idea according to ben in classified information and the last to vote yes). the rules are certain, this night is not. peter resorts to drinking, his old favorite method of dealing with uncertainty. and the drinking exacerbates his impulsivity, so we get that classic lethal peter combo of avoidance (ignoring balth in the kitchen) and thoughtless flirting (sitting half on top of him on the couch)

and balthazar, who at first seems to have escaped unscathed and returns from zeb's in a cheerful mood - when he finds out what went down with peter, it's like the guilt erases his memory of the previous night. he indicates that he thinks peter drank too much because of balth going home with someone else, but in actuality, peter was drinking heavily way before that! the edit juxtaposes multiple shots of an unsmiling balthazar with shots of peter drinking throughout the party. when they hug, peter can't even properly embrace balth because of the drinks he's double-fisting - ouch! symbolic!! perhaps balth leaving with zeb made peter go overboard, but ben does say that his last conversation with peter was a happy one, so i don't think we really know for sure how it affected peter or if peter was even lucid enough to realize balth left. we're only getting it from balth's pov. and as usual, balth can't see things clearly once peter is involved and defaults to torturing himself over it, which i suppose is why he has to be the first to leave (thank you john)