Growing up in a bar you get over awkwardness about witnessing fights people should maybe have had in private real quickly. Jo remembers one, in fact, Uncle John had been there for, some guy sleeping with some other guy's girlfriend and her mom marching them both out to the parking lot with her shotgun, haranguing them for their language, and her dad laughing even as he tried to explain to Jo that these men were behaving Very Badly and were going for their time out. This little Winchester Family Drama is nothing like those fights though, no screaming or cursing or showy behavior to make it so over the top it's funny. She's not even sure it could properly be called a fight so much as a series of rapid, decidedly fucked-up, interplays by people who seem to have suddenly swapped their personalities in for new ones-- Sam is suddenly snippy and difficult instead of conciliatory and sweet, Dean is completely devoid of the bravado she's never seen him without and looking like he's trying to keep tabs on everyone at once, and Uncle John is...well her expression as she watches him could have clued space aliens into the fact that she hadn't expected anything like this from him.
>>“Don't get smart with me. You get up, Sam, and you thank Jo. We'll be hitting the road soon as her mother'n me have had a few words”
Whoa, wait, what? Jo thinks, shooting a look at Dean automatically. I thought they were going to stick around for awhile...why take off with Sam still healing up? What if something happens again, shouldn't they be somewhere we can all deal with it? She opens her mouth to say as much but loses her nerve when she sees John's face, teeth clicking together again near-audibly and she steps back to give him room as he barks another order and then turns and heads out. Dean gives her an awkward smile as he passes and she grimaces sympathetically at him in return, bumping his arm a little with her elbow as she moves past him towards Sam. The gesture's a little familiar for someone you've only known a couple days, the assumption that it's her place to do anything besides awkwardly ignore what she's just seen much less offer that kind of 'shoring up' gesture, but it'd been automatic because as weird as this is for her she wouldn't trade places with Dean and be in the middle of that either and... oh whatever, he's a nice guy despite himself, you can be sympathetic without writing a damn mental thesis on it.
The mental rambling had been the work of seconds and she's shaken it off by the time she comes up alongside Sam, cocking her head slightly and raising her eyebrows. “Well, uh, shit,” she mutters, shaking her head.