I think if Prim had trouble sleeping tonight and Gale was a bit restless too (our current night) then I think both could be done at the same time. Gale and Prim are both doing this for the first time and could find comfort in each other, whereas with Katniss, she's struggling with something else entirely and it might be unfair to expect Gale or Prim to comfort her, just as it would be hard for Katniss to be able to fully calm Prim down as much as she'd want to. So if Gale notices Prim isn't sleeping, he'd surely try and do something to try and ease her mind. And then we could have Katniss and Haymitch doing their own thing elsewhere. Would that work you think? ^^